Analysts and Investors Day June 2017 Main Street Capital - PowerPoint PPT Presentation

LMM Investment Portfolio Median LMM portfolio credit statistics: LMM Investment Portfolio • Senior leverage of 2.8x EBITDA to MAIN debt position is a pool of high quality, • 2.6x EBITDA to senior interest coverage seasoned assets with • Total leverage of 3.2x EBITDA including debt junior in priority to attractive risk-adjusted MAIN return characteristics • Free cash flow de-leveraging improves credit metrics and increases equity appreciation Average investment size of $10.6 million (less than 1% of total investment portfolio) Opportunistic, selective posture toward new investment activity over the economic cycle High quality, seasoned LMM portfolio • Total LMM portfolio investments at fair value equals 115% of cost • Equity component of LMM portfolio at fair value equals 165% of cost • Majority of LMM portfolio has de-leveraged and experienced equity appreciation – 45 LMM portfolio companies with net unrealized appreciation on equity investments as of March 31, 2017 – Net unrealized appreciation on LMM equity investments of $161 million as of March 31, 2017 Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 7

LMM Portfolio by Industry (as a Percentage of Cost) Energy Equipment & Services, 14% Machinery, 9% Construction & Engineering, 8% Hotels, Restaurants & Leisure, 7% Specialty Retail, 5% Computers & Peripherals, 5% Electronic Equipment, Instruments & Components, 5% Diversified Telecommunication Services, 4% Internet Software & Services, 4% Building Products, 4% Leisure Equipment & Products, 4% Diversified Consumer Services, 4% Health Care Equipment & Supplies, 3% Diversified Financial Services, 3% Commercial Services & Supplies, 3% Software, 3% IT Services, 2% Professional Services, 2% Health Care Providers & Services, 2% Consumer Finance, 2% Oil, Gas & Consumable Fuels, 1% Air Freight & Logistics, 1% Chemicals, 1% Paper & Forest Products, 1% Other, 3% Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 8

Diversified LMM Portfolio (as a Percentage of Cost) Invested Capital by Transaction Type Invested Capital by Geography (1) LBO/MBO Recapitalization/ Refinancing 37% 18% 7% 23% 38% 12% 40% 3% 22% Acquisition Growth Capital (1) Based upon portfolio company headquarters Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 9

A Mature and Diversified Portfolio – LMM Investments Greater than Five Years Old ($ in 000's) Remaining Initial Equity Ownership % Investment Type Investment Date Fair Value Annual ROE In MAIN portfolio for > 10 years (1) 1 Houston Plating and Coatings, LLC Equity Only Jan-03 < 25% 4,230 2 Café Brazil, LLC Equity Only Apr-04 > 50% 5,900 3 KBK Industries, LLC Debt and Equity Jan-06 < 25% 9,847 4 Hawthorne Customs and Dispatch Services, LLC Equity Only Jan-06 25% to 50% 2,320 5 East Teak Fine Hardwoods, Inc. Equity Only Apr-06 < 25% 750 6 CBT Nuggets, LLC Equity Only Jun-06 25% to 50% 60,620 7 Jensen Jewelers of Idaho, LLC Debt and Equity Nov-06 > 50% 8,365 8 Mid-Columbia Lumber Products, LLC Debt and Equity Dec-06 > 50% 9,675 9 Vision Interests, Inc. Debt and Equity Jun-07 > 50% 5,814 Total - In MAIN portfolio for > 10 years 107,521 % of total LMM portfolio at fair value 12% In MAIN portfolio for > 8 years (1) 10 Gulf Manufacturing, LLC Debt and Equity Aug-07 25% to 50% 9,967 11 The MPI Group, LLC Debt and Equity Oct-07 > 50% 5,312 12 Hydratec, Inc. Equity Only Nov-07 > 50% 15,640 13 Uvalco Supply, LLC Debt and Equity Jan-08 > 50% 5,063 14 NAPCO Precast, LLC Debt and Equity Feb-08 25% to 50% 17,585 15 OMi Holdings, Inc. Equity Only Apr-08 25% to 50% 13,080 16 Lamb Ventures, LLC Debt and Equity May-08 > 50% 15,862 17 Condit Exhibits, LLC Equity Only Jul-08 < 25% 1,840 18 Ziegler’s NYPD, LLC Debt and Equity Oct-08 > 50% 8,384 Total - In MAIN portfolio for > 8 years 200,254 % of total LMM portfolio at fair value 23% (1) Aging as of June 8, 2017; fair value as of March 31, 2017 Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 10

A Mature and Diversified Portfolio – LMM Investments Greater than Five Years Old (continued) ($ in 000's) Remaining Initial Equity Ownership % Investment Type Investment Date Fair Value Annual ROE In MAIN portfolio for > 6 years (1) 19 Indianapolis Aviation Partners, LLC Debt and Equity Sep-09 25% to 50% 5,810 20 Compact Power Equipment Centers Inc. Debt and Equity Sep-09 < 25% 8,680 21 Drilling Info Holdings, Inc. (2) Equity Only Nov-09 < 25% 10,100 22 Harrison Hydra-Gen, Ltd. Equity Only Jun-10 25% to 50% 2,800 23 PPL RVs, Inc. Debt and Equity Jun-10 > 50% 29,614 24 OPI International Ltd. Debt and Equity Nov-10 < 25% 853 25 irth Solutions, LLC (2) Equity Only Dec-10 < 25% 1,920 26 Pegasus Research Group, LLC Equity Only Jan-11 25% to 50% 8,440 27 Principle Environmental, LLC Debt and Equity Feb-11 > 50% 14,034 28 River Aggregates, LLC Debt and Equity Mar-11 25% to 50% 7,756 29 OnAsset Intelligence, Inc. Debt and Equity Apr-11 < 25% 4,654 Total - In MAIN portfolio for > 6 years 294,915 % of total LMM portfolio at fair value 33% In MAIN portfolio for > 5 years (1) 30 NRI Clinical Research, LLC Debt and Equity Sep-11 25% to 50% 7,803 31 SAFETY Investment Holdings, LLC (2) Equity Only Nov-11 < 25% 2,000 32 Gault Financial, LLC (RMB Capital, LLC) Debt and Equity Nov-11 < 25% 11,950 33 NRP Jones, LLC Debt and Equity Dec-11 > 50% 14,594 34 Ameritech College Operations, LLC Debt and Equity Mar-12 25% to 50% 6,839 35 Bridge Capital Solutions Corporation Debt and Equity Apr-12 25% to 50% 11,043 Total - In MAIN portfolio for > 5 years 349,144 % of total LMM portfolio at fair value 39% (1) Aging as of June 8, 2017; fair value as of March 31, 2017 Since MAIN’s initial investment in this portfolio company, the portfolio company has completed one or more transactions where by it sold or recapitalized a majority of its (2) equity, and through these transactions MAIN retained a portion of its equity ownership in the portfolio company. The investment date listed here represents MAIN’s initial investment date in each portfolio company Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 11

Portfolio Investments – Vintage Analysis ($ Invested) (1) Lower Middle Market Middle Market Annual ROE $400.0 $400.0 $350.0 $350.0 ($) in millions ($) in millions $300.0 $300.0 $250.0 $250.0 $200.0 $200.0 $150.0 $150.0 $100.0 $100.0 $50.0 $50.0 $- $- 2011 and 2012 2013 2014 2015 2016 2017 2011 and 2012 2013 2014 2015 2016 2017 prior prior Cost Fair Value Cost Fair Value Total (2) Private Loan $400.0 $400.0 $350.0 $350.0 $300.0 $300.0 ($) in millions ($) in millions $250.0 $250.0 $200.0 $200.0 $150.0 $150.0 $100.0 $100.0 $50.0 $50.0 $- $- 2011 and 2012 2013 2014 2015 2016 2017 2011 and 2012 2013 2014 2015 2016 2017 prior prior Cost Fair Value Cost Fair Value (1) As of March 31, 2017 Including Other Portfolio investments and excluding MAIN’s external investment manager, MSC Advisor I, LLC (2) Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 12

Portfolio Investments – Vintage Analysis (% Invested) (1) Lower Middle Market Middle Market 40% 35% 35% 30% 30% 25% % of total % of total 25% 20% 20% 15% 15% 10% 10% 5% 5% 0% 0% 2011 and 2012 2013 2014 2015 2016 2017 2011 and 2012 2013 2014 2015 2016 2017 prior prior Cost Fair Value Cost Fair Value Private Loan Total (2) 35% 25% 30% 20% 25% % of total % of total 15% 20% 15% 10% 10% 5% 5% 0% 0% 2011 and 2012 2013 2014 2015 2016 2017 2011 and 2012 2013 2014 2015 2016 2017 prior prior Cost Fair Value Cost Fair Value (1) As of March 31, 2017 Including Other Portfolio investments and excluding MAIN’s external investment manager, MSC Advisor I, LLC (2) Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 13

Middle Market Liquidity Analysis (1) Contractual Maturity Contractual Maturity $160.0 30% $140.0 25% ($) in millions $120.0 % of total 20% $100.0 $80.0 15% $60.0 10% $40.0 5% $20.0 $- 0% 2017 2018 2019 2020 2021 2022 2023 2024 2017 2018 2019 2020 2021 2022 2023 2024 Principal Principal Expected Maturity (2) Expected Maturity (2) $180.0 30% $160.0 25% $140.0 ($) in millions $120.0 20% % of total $100.0 15% $80.0 $60.0 10% $40.0 5% $20.0 $- 0% 2017 2018 2019 2020 2021 2022 2023 2024 2017 2018 2019 2020 2021 2022 2023 2024 Principal Principal (1) As of March 31, 2017; amounts and percentages are based upon the par value of debt investments Expected Maturity represents MAIN’s estimated or anticipated repayment date based on historical trends in both MAIN’s portfol io and in the broader Middle Market (2) Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 14

Asset Management Business MAIN’s asset In May 2012, MAIN (1) entered into an investment sub-advisory management business agreement with the investment advisor to HMS Income Fund, Inc. represents additional (HMS), a non-listed BDC • MAIN (1) provides asset management services, including sourcing, income diversification and the opportunity for diligence and post-investment monitoring greater shareholder • HMS has total assets of $1.0 billion as of March 31, 2017 returns • MAIN (1) receives 50% of the investment advisor’s base asset management fee and incentive fees – MAIN (1) base asset management fee – 1% of total assets – MAIN (1) incentive fees – 10% of net investment income above a hurdle and 10% of MAIN’s internally net realized capital gains managed operating structure provides Benefits to MAIN MAIN’s shareholders the • No significant increases to MAIN’s operating costs to provide benefits of this asset services (utilize existing infrastructure and leverage fixed costs) management business • No invested capital – monetizing the value of MAIN franchise • Impact on MAIN’s financial results – $2.2 million contribution to net investment income in the first quarter of 2017 (2) – $7.9 million contribution to net investment income for the year ended December 31, 2016 (2) – $33.5 million of cumulative unrealized appreciation as of March 31, 2017 Through MAIN’s wholly owned unconsolidated subsidiary, MSC Advisor I, LLC (1) (2) Contribution to Net Investment Income includes (a) dividend income received by MAIN from MSC Advisor I, LLC and (b) operating expenses allocated from MAIN to MSC Advisor I, LLC Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 15

Alignment of Interests Between MAIN Management and MAIN Investors Management Alignment – Has asset growth been accretive to shareholders – earnings, dividend, NAV per share? MAIN Growth % Total Total Assets DNII Per Dividends NAV Per Share (1) Per Share (2) Assets Per Share Share 1-YR 11% 3% 3% 4% 4% 3-YR 53% 12% 10% 17% 11% 5-YR 182% 39% 35% 39% 45% From End of IPO Year 1089% 96% 214% 65% 72% – Benefits of internally managed structure • Greater incentives to maximize increases to shareholder value and rationalize equity and debt capital raises • No conflicts of interests; 100% of MAIN’s management efforts and activities are for the benefit of the BDC – Favorable comparison of the above vs our peers, the vast majority of which have only increased assets under management, but not key shareholder value metrics Management Ownership – MAIN’s senior executives and Board of Directors own 3.2 million shares worth ~$121 million (3) • $24.0 million purchased as part of or since 2007 IPO, including $3.8 million purchased in 2016 and Q1 2017 – Broad / significant ownership throughout greater MAIN team through restricted stock • Focuses our personnel on key drivers of value to MAIN shareholders – DNII and NAV per share • Restricted stock grants were greater than 40% of 2016 total compensation for executive management (1) Distributable net investment income (DNII) is net investment income excluding the impact of share-based compensation expense which is non-cash in nature (2) Excludes supplemental/special dividends (3) Based upon closing market price of $38.27/share on March 31, 2017 Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 16

MAIN Maintains a Significant Operating Cost Advantage Operating Expenses as a Percentage of Total Assets (1) Efficient and 4.0% leverageable operating structure 3.5% MAIN’s internally 3.0% managed operating 2.5% structure provides significant operating 2.0% leverage and greater 1.5% returns for our shareholders 1.0% 0.5% Other Commercial MAIN (2) BDCs (3)(4) Banks (5) 0.0% (1) Total operating expenses, including non-cash share based compensation expense and excluding interest expense (2) For the trailing twelve month period ended March 31, 2017 (3) Other BDCs includes dividend paying BDCs that have been publicly-traded for at least two years and have total assets greater than $500 million based on individual SEC Filings as of December 31, 2016; specifically includes: AINV, ARCC, BKCC, CPTA, FDUS, FSC, FSFR, FSIC, GBDC, HTGC, MCC, MFIN, NMFC, PFLT, PNNT, PSEC, SLRC, SUNS, TCAP, TCPC, TCRD, TICC and TSLX (4) Calculation represents the average for the companies included in the group and is based upon the trailing twelve month period ended December 31, 2016 as derived from each company’s SEC filings (5) Source: SNL Financial. Calculation represents the average for the trailing twelve month period ended December 31, 2016 and includes commercial banks with a market capitalization between $125 million and $2 billion Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 17

MAIN Maintains a Significant Operating Cost Advantage BDC Manager Costs Relative to Total Economic Profit Generated (dollars in thousands) 5 Year Total (1)(2) Annual ROE Gross Economic Net Increase in Add back: Profit Before % Economic Dividend Paying BDCs Management Net Assets Compensation Management Profits Paid to Public for > 2 Years (3) Structure (Net Income) and Mgmt Fees Costs Management MAIN Internal $ 545,329 $ 81,720 $ 627,049 13.0% Apollo Investment Corporation External 319,975 493,546 813,521 60.7% Ares Capital Corporation External 2,513,000 1,200,033 3,713,033 32.3% BlackRock Capital Investment Corporation External 241,913 191,871 433,784 44.2% Capitala Finance Corp. External 19,562 43,221 62,783 68.8% Fidus Investment Corporation External 133,646 64,534 198,180 32.6% Fifth Street Finance Corp. External 242,593 336,785 579,378 58.1% Fifth Street Senior Floating Rate Corp. External 20,818 25,278 46,096 54.8% FS Investment Corporation External 332,676 238,472 571,148 41.8% Golub Capital BDC, Inc. External 283,663 123,339 407,002 30.3% Hercules Capital, Inc. Internal 329,012 125,497 454,509 27.6% Medley Capital Corporation External 71,260 138,193 209,453 66.0% New Mountain Finance Corporation External 190,208 100,534 290,742 34.6% PennantPark Floating Rate Capital Ltd. External 90,453 27,809 118,262 23.5% PennantPark Investment Corporation External 274,605 193,530 468,135 41.3% Prospect Capital Corporation External 1,180,481 933,998 2,114,479 44.2% Solar Capital Ltd. External 360,418 197,466 557,884 35.4% Solar Senior Capital Ltd. External 63,519 14,973 78,492 19.1% TCP Capital Corp. External 219,460 59,942 279,402 21.5% THL Credit, Inc. External 152,452 91,667 244,119 37.6% TICC Capital Corp. External 168,148 109,173 277,321 39.4% TPG Specialty Lending, Inc. External 200,575 87,756 288,331 30.4% Triangle Capital Corporation Internal 251,751 89,388 341,139 26.2% Peer Group Average 39.6% (1) Source: Public company filings (2) Amounts represent the most recent five prior fiscal years ended for each respective company. For each applicable BDC not > 5 years past IPO, the first full fiscal year-end post-IPO was used as the starting point for this analysis as follows: CPTA – 2014; FSFR – 2014; FSIC – 2015; TCPC – 2013 and TSLX – 2015. NMFC amounts represent the most recent three prior fiscal years since management fees were not presented for FY 2012 and FY 2013 in NMFC’s SEC filings (3) Includes all BDCs with total assets greater than $500 million as of December 31, 2016, with the exception of MFIN which is excluded due to the non-traditional nature of their business plan and operations compared to most BDCs Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 18

Historical Dividend, DNII and NAV Per Share Growth $0.90 $24.00 MAIN’s unique focus Recessionary on equity investments $22.00 $0.80 Period in the Lower Middle DNII and Dividends Per Share $20.00 Market provides the $0.70 NAV Per Share opportunity for $18.00 $0.60 significant NAV per $16.00 share growth $0.50 $14.00 MAIN’s efficient $0.40 operating structure $12.00 provides significant $0.30 $10.00 operating leverage, Internally Externally greater dividends and $0.20 $8.00 Managed Managed $0.00 207 Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3 BDC’s (3)(5) BDC’s (4)(5) greater overall returns MAIN (2) 2007 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 for our shareholders Regular Dividends Supplemental Dividends DNII per share NAV per share MAIN’s dividends have been covered by DNII • Includes recurring monthly and supplemental dividends paid and declared and net realized gains as of June 7, 2017. – MAIN has never paid • Annual return on equity averaging approximately 13.8% from 2010 through a return of capital the first quarter of 2017 distribution Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 19

MAIN Strategy Produces Differentiated Returns Historical Monthly Dividend Growth and Coverage of Monthly Dividends with Earnings (1) Coverage? Dividend Paying BDCs Dividends Per Share Monthly Dividends Per Share 5-YR 3-YR 2016 NII / Public for > 5 Years (2) CAGR CAGR Mo. Dividend 2011 2012 2013 2014 2015 2016 MAIN $1.56 $1.71 $1.86 $2.00 $2.10 $2.18 6.87% 5.35% 102.3% Apollo Investment Corporation $1.12 $1.04 $0.80 $0.80 $0.80 $0.75 -7.71% -2.13% 93.2% Ares Capital Corporation $1.41 $1.50 $1.52 $1.52 $1.52 $1.52 1.51% 0.00% 103.5% BlackRock Capital Investment Corporation $1.10 $1.04 $1.04 $0.94 $0.84 $0.84 -5.25% -6.87% 88.4% Fidus Investment Corporation N/A $1.46 $1.52 $1.52 $1.54 $1.56 NM 0.87% 93.3% Fifth Street Finance Corporation $1.28 $1.18 $1.15 $1.03 $0.69 $0.72 -10.87% -14.45% 98.7% Golub Capital BDC, Inc. $1.28 $1.28 $1.28 $1.28 $1.28 $1.28 0.00% 0.00% 98.9% Hercules Capital, Inc. $0.88 $0.95 $1.11 $1.24 $1.24 $1.24 7.10% 3.76% 109.7% Medley Capital Corporation N/A $1.31 $1.46 $1.48 $1.20 $1.04 NM -10.69% 84.1% New Mountain Finance Corporation N/A $1.34 $1.36 $1.36 $1.36 $1.36 NM 0.00% 88.9% PennantPark Floating Rate Capital Ltd. N/A $0.94 $1.04 $1.08 $1.13 $1.14 NM 3.11% 95.4% Pennant Park Investment Corp. $1.07 $1.12 $1.12 $1.12 $1.12 $1.12 0.92% 0.00% 86.3% Prospect Capital Corporation $1.21 $1.22 $1.28 $1.33 $1.05 $1.00 -3.75% -7.91% 95.9% Solar Capital Ltd. $2.40 $1.80 $2.20 $1.60 $1.60 $1.60 -7.79% -10.07% 105.2% Solar Senior Capital Ltd. N/A $1.16 $1.41 $1.41 $1.41 $1.41 NM 0.00% 100.9% THL Credit, Inc. $1.17 $1.29 $1.43 $1.36 $1.36 $1.29 1.97% -3.38% 104.4% TICC Capital Corp. $0.99 $1.12 $1.16 $1.16 $1.14 $1.16 3.22% 0.00% 39.9% Triangle Capital Corporation $1.77 $2.02 $2.16 $2.16 $2.16 $1.89 1.32% -4.35% 85.6% Peer Group Average -1.61% -3.07% 92.5% (1) Sources: Yearly dividends per share from individual company website; does not include supplemental dividends (2) Includes all BDCs with total assets greater than $500 million as of December 31, 2016, with the exception of MFIN, which is excluded due to the non-traditional nature of their business plan and operations compared to most BDCs Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 20

MAIN Strategy Produces Differentiated Returns Dividend Yield Does Not Equal Economic Shareholder Return and Can Be Very Misleading Return of Capital Distributions Do Not Equal Investment Return to Shareholders Total Distributions Avg Dist Paid Net Excess Avg Adj'd Realized Income Per Paid Per Share Per Yr as a Earnings / Profit Dist Per Share 2011 - 2016 (2) 2011 - 2016 (3) Dividend Paying BDCs % of Beg Mkt (Return of Yr as % of Beg Public for > 2 Years (1) Price (4) Capital) (5) Mkt Price (6) Cumulative Cumulative MAIN 13.93 13.85 12.7% 0.08 12.8% Apollo Investment Corporation 1.17 5.31 8.0% (4.14) 1.8% Ares Capital Corporation 11.11 9.24 9.3% 1.87 11.2% BlackRock Capital Investment Corporation 4.09 5.80 8.7% (1.71) 6.2% Capitala Finance Corp. 4.02 5.76 9.6% (1.74) 6.7% Fidus Investment Corporation 9.00 8.32 12.8% 0.68 13.9% Fifth Street Finance Corp. 3.14 6.05 8.3% (2.91) 4.3% Fifth Street Senior Floating Rate Corp. 3.15 3.20 8.1% (0.05) 7.9% FS Investment Corporation 1.43 1.63 8.2% (0.21) 7.2% Golub Capital BDC, Inc. 7.62 7.93 7.7% (0.31) 7.4% Hercules Capital, Inc. 7.56 6.66 10.7% 0.90 12.2% Medley Capital Corporation 4.69 6.49 12.5% (1.80) 9.0% New Mountain Finance Corporation 6.38 7.39 11.0% (1.01) 9.5% PennantPark Floating Rate Capital Ltd. 5.99 5.32 10.3% 0.67 11.6% PennantPark Investment Corp. 6.15 6.67 9.1% (0.52) 8.4% Prospect Capital Corporation 6.65 7.09 10.9% (0.43) 10.3% Solar Capital Ltd. 8.21 11.20 7.5% (2.99) 5.5% Solar Senior Capital Ltd. 6.02 6.80 6.2% (0.78) 5.5% TCP Capital Corp. 4.96 5.95 10.1% (0.99) 8.4% THL Credit, Inc. 6.58 7.95 10.2% (1.37) 8.4% TICC Capital Corp. 5.19 6.73 10.0% (1.54) 7.7% TPG Specialty Lending, Inc. 3.54 3.12 9.3% 0.42 10.5% Triangle Capital Corporation 13.48 12.76 11.2% 0.72 11.8% Peer Group Average 9.5% 8.4% (1) Includes all BDCs with total assets greater than $500 million as of December 31, 2016, with the exception of MFIN, which is excluded due to the non-traditional nature of their business plan and operations compared to most BDCs (2) Realized Income = Net Investment Income plus Net Realized Gains / (Losses) on investments (3) Includes Total Distributions Paid to shareholders (4) Calculation is (a) (i) Total Distributions Paid divided by (ii) Beginning Market Price Per Share divided by (b) number of years included in analysis (based upon each company's respective IPO date). For each applicable BDC not > 6 years past IPO, the first full 12/31 calendar year-end post-IPO is as follows: CPTA – 2014; FDUS – 2012; FSFR – 2014; FSIC – 2015; MCC – 2012; NMFC – 2012; PFLT – 2012; SUNS – 2012; TCPC – 2013 and TSLX – 2015. (5) Realized Income Per Share minus Total Distributions Paid Per Share (6) Adjusted Profit Distributions = Total Distributions Paid Per Share plus Net Excess Earnings / (Return of Capital); % result is based upon the same calculation as footnote (4) above Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 21

MAIN Strategy Produces Differentiated Returns Total Shareholder Returns are Better Indicator of Economic Value Creation for Shareholders Total Shareholder Return - Economic Value Total Shareholder Return - Market Value Net Asset Increase Distributions NAV Change Avg Ann'l Closing Trading Increase Distributions Mkt Price Chg Avg Ann'l Dividend Paying BDCs Public Value Per Share (Decrease) in Paid Per Share Plus Distrib Return as a % Price Per Share (Decrease) in Paid Per Share Plus Distrib Return as a % for > 2 Years (1) Beg (2) 2011-2016 (3) of Beg NAV (4) Beg (2) 2011-2016 (3) Beg Mkt Price (5) 12/31/16 NAV Per Share Per Share 12/31/16 Market Price Per Share MAIN 13.06 22.10 9.04 13.85 22.89 29.2% 18.19 36.77 18.58 13.85 32.43 29.7% Apollo Investment Corporation 9.73 6.86 (2.87) 5.31 2.44 4.2% 11.07 5.86 (5.21) 5.31 0.10 0.2% Ares Capital Corporation 14.92 16.45 1.53 9.24 10.77 12.0% 16.48 16.49 0.01 9.24 9.25 9.4% BlackRock Capital Investment Corporation 9.62 8.21 (1.41) 5.80 4.39 7.6% 11.06 6.96 (4.10) 5.80 1.70 2.6% Capitala Finance Corp. 20.71 15.79 (4.92) 5.76 0.84 1.4% 19.90 12.93 (6.97) 5.76 (1.21) -2.0% Fidus Investment Corporation 14.90 15.76 0.86 8.32 9.18 12.3% 12.97 15.73 2.76 8.32 11.08 17.1% Fifth Street Finance Corp. 10.44 7.31 (3.13) 6.05 2.92 4.7% 12.14 5.37 (6.77) 6.05 (0.72) -1.0% Fifth Street Senior Floating Rate Corp. 15.10 10.86 (4.24) 3.20 (1.04) -2.3% 13.24 8.71 (4.53) 3.20 (1.33) -3.3% FS Investment Corporation 9.83 9.41 (0.42) 1.63 1.21 6.2% 9.93 10.30 0.37 1.63 2.00 10.1% Golub Capital BDC, Inc. 14.74 15.74 1.00 7.93 8.93 10.1% 17.12 18.39 1.27 7.93 9.20 9.0% Hercules Capital, Inc. 9.50 9.90 0.40 6.66 7.06 12.4% 10.36 14.11 3.75 6.66 10.41 16.7% Medley Capital Corporation 12.57 9.39 (3.18) 6.49 3.31 5.3% 10.40 7.51 (2.89) 6.49 3.60 6.9% New Mountain Finance Corporation 13.60 13.46 (0.14) 7.39 7.25 10.7% 13.41 14.10 0.69 7.39 8.08 12.1% PennantPark Floating Rate Capital Ltd. 13.68 14.11 0.43 5.32 5.75 8.4% 10.30 14.11 3.81 5.32 9.13 17.7% PennantPark Investment Corp. 11.14 9.11 (2.03) 6.67 4.64 6.9% 12.25 7.66 (4.59) 6.67 2.08 2.8% Prospect Capital Corporation 10.25 9.62 (0.63) 7.09 6.46 10.5% 10.80 8.35 (2.45) 7.09 4.64 7.2% Solar Capital Ltd. 22.73 21.74 (0.99) 11.20 10.21 7.5% 24.78 20.82 (3.96) 11.20 7.24 4.9% Solar Senior Capital Ltd. 18.15 16.80 (1.35) 6.80 5.45 6.0% 22.09 16.44 (5.65) 6.80 1.15 1.0% TCP Capital Corp. 14.71 14.91 0.20 5.95 6.15 10.5% 14.74 16.90 2.16 5.95 8.11 13.8% THL Credit, Inc. 13.06 11.82 (1.24) 7.95 6.71 8.6% 13.01 10.01 (3.00) 7.95 4.95 6.3% TICC Capital Corp. 9.85 7.50 (2.35) 6.73 4.38 7.4% 11.21 6.61 (4.60) 6.73 2.13 3.2% TPG Specialty Lending, Inc. 15.53 15.95 0.42 3.12 3.54 11.4% 16.82 18.68 1.86 3.12 4.98 14.8% Triangle Capital Corporation 12.09 15.13 3.04 12.76 15.80 21.8% 19.00 18.34 (0.66) 12.76 12.10 10.6% Peer Group Average 8.3% 7.3% (1) Includes all BDCs with total assets greater than $500 million as of December 31, 2016, with the exception of MFIN, which is excluded due to the non-traditional nature of their business plan and operations compared to most BDCs (2) Represents either (a) 12/31/10 if BDC has been public > 6 years or (b) the first 12/31 date after IPO date. For each applicable BDC not > 6 years past IPO, the beginning 12/31 period is as follows: CPTA – 12/31/13; FDUS – 12/31/11; FSFR – 12/31/13; FSIC – 12/31/14; MCC – 12/31/11; NMFC – 12/31/11; PFLT – 12/31/11; SUNS – 12/31/11; TCPC – 12/31/12 and TSLX 12/31/14 (3) Represents either (a) dividends for full 6 years if BDC has been public > 6 years or (b) dividends from first full 12/31 calendar year-end after IPO date through 12/31/16. See footnote (4) on page 21 for details (4) Calculation is (a) (i) Total NAV Change Plus Distributions Paid per Share divided by (ii) Beginning NAV divided by (b) number of years included in analysis (based upon IPO date) (5) Calculation is (a) (i) Total Market Price Change Plus Distributions Paid per Share divided by (ii) Beginning Market Price divided by (b) number of years included in analysis (based upon IPO date) Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 22

MAIN Strategy Produces Differentiated Returns Preserving (or Increasing) Value through Economic Cycles? Declining NAV = Risk to Investors Current NAV/ NAV / Share NAV/Share Dividend Paying BDCs Cumulative Equity 5-YR 3-YR % Growth Public for > 5 years (1) Capital Raised (2) CAGR CAGR 12/31/2011 12/31/2016 (Decline) MAIN $15.19 $22.10 45.5% 7.8% 3.6% 105% Apollo Investment Corporation $8.16 $6.86 -15.9% -3.4% -7.2% 50% Ares Capital Corporation $15.34 $16.45 7.2% 1.4% 0.0% 98% BlackRock Capital Investment Corporation $9.58 $8.21 -14.3% -3.0% -4.9% 68% Fidus Investment Corporation $14.90 $15.76 5.8% 1.1% 0.9% 104% Fifth Street Finance Corporation $9.89 $7.31 -26.1% -5.9% -9.5% 65% Golub Capital BDC, Inc. $14.53 $15.74 8.3% 1.6% 1.1% 101% Hercules Capital, Inc. $9.83 $9.90 0.7% 0.1% -2.0% 94% Medley Capital Corporation $12.57 $9.39 -25.3% -5.7% -9.5% 72% New Mountain Finance Corporation $13.60 $13.46 -1.0% -0.2% -2.2% 94% PennantPark Floating Rate Capital Ltd. $13.68 $14.11 3.1% 0.6% -0.3% 102% PennantPark Investment Corp. $10.19 $9.11 -10.6% -2.2% -5.5% 79% Prospect Capital Corporation $10.69 $9.62 -10.0% -2.1% -3.6% 87% Solar Capital Ltd. $22.02 $21.74 -1.3% -0.3% -1.1% 93% Solar Senior Capital Ltd. $18.15 $16.80 -7.4% -1.5% -2.3% 94% THL Credit, Inc. $13.24 $11.82 -10.7% -2.2% -4.0% 89% TICC Capital Corp. $9.30 $7.50 -19.4% -4.2% -8.7% 69% Triangle Capital Corporation $14.68 $15.13 3.1% 0.6% -2.1% 89% Peer Group Average -6.7% -1.5% -3.6% 85% Note: MAIN NAV/Share growth p rimarily generated through retained earnings (3) (~25%) and accretive offerings (~75%) Source: Individual company filings (1) Includes all BDCs with total assets greater than $500 million as of December 31, 2016, with the exception of MFIN, which is excluded due to the non-traditional nature of their business plan and operations compared to most BDCs (2) As of December 31, 2016 (3) Retained earnings includes cumulative net investment income, net realized gains and net unrealized appreciation, net of cumulative dividends paid or accrued Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 23

MAIN Strategy Produces Differentiated Returns Operating Efficiency and Superior Underwriting Produces Superior Returns Annual Return on Equity (ROE) (1) Annual ROE Dividend Paying BDCs Public for > 2 Years (2) 7-YR 5-YR 3-YR MAIN (3) 14.1% 13.3% 11.7% Apollo Investment Corporation 4.0% 6.0% 2.0% Ares Capital Corporation 12.1% 10.5% 9.3% BlackRock Capital Investment Corporation 8.0% 6.8% 4.2% Capitala Finance Corp. N/A N/A 2.5% Fidus Investment Corporation N/A 11.8% 11.4% Fifth Street Finance Corp. 2.9% 2.7% -1.2% Fifth Street Senior Floating Rate Corp. N/A N/A 2.3% FS Investment Corporation N/A N/A N/A Golub Capital BDC, Inc. N/A 9.1% 9.0% Hercules Capital, Inc. 9.5% 10.3% 8.6% Medley Capital Corporation N/A 3.0% 0.1% New Mountain Finance Corporation N/A 8.1% 7.9% PennantPark Floating Rate Capital Ltd. N/A 8.6% 8.1% PennantPark Investment Corp. 7.5% 8.3% 4.9% Prospect Capital Corporation 9.1% 8.5% 7.4% Solar Capital Ltd. N/A 7.8% 6.1% Solar Senior Capital Ltd. N/A 6.3% 5.8% TCP Capital Corporation N/A N/A 8.2% THL Credit, Inc. N/A 7.7% 6.4% TICC Capital Corp. 8.7% 7.5% 2.9% TPG Specialty Lending, Inc. N/A N/A N/A Triangle Capital Corporation 11.9% 10.6% 7.1% Peer Group Average 8.2% 7.8% 5.7% (1) ROE calculated as Net Increase in Net Assets divided by average Net Asset Value for each respective measurement period through December 31, 2016 (2) Includes all BDCs with total assets greater than $500 million as of December 31, 2016, with the exception of MFIN, which is excluded due to the non-traditional nature of their business plan and operations compared to most BDCs. (3) MAIN Net Increase in Net Assets in ROE calculation excludes impact from changes in fair value (unrealized or realized) relating to SBIC debentures Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 24

Perspective on Total Return Since IPO Total Return (%)* Annual Total Return (%)* MAIN MAIN TCAP TCAP NEWT NEWT ARCC ARCC HTGC HTGC CSWC CSWC GAIN GAIN TICC TICC PNNT PNNT SAR SAR PSEC PSEC BKCC BKCC AINV AINV MVC MVC KCAP KCAP MFIN MFIN OHAI OHAI -100% 25% 150% 275% 400% 525% -20% -14% -8% -2% 4% 10% 16% 22% *Note: Bloomberg data from BDCs in existence since October 5, 2007 and assuming dividends were reinvested in each security; return analysis is through June 1, 2017 Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 25

Perspective on Total Return Since IPO Amongst current S&P 500 constituents in existence since October 5, 2007, MAIN’s Total Return Since IPO ranks #22 – This result places MAIN’s total return performance in the top 5% of this comparable group # Company Total Return # Company Total Return 1 NETFLIX INC 5086.0% 14 APPLE INC 634.7% 2 REGENERON PHARMACEUTICALS 2490.4% 15 REYNOLDS AMERICAN INC 632.8% 3 PRICELINE GROUP INC/THE 1913.0% 16 O'REILLY AUTOMOTIVE INC 632.4% 4 INCYTE CORP 1610.1% 17 ALLERGAN PLC 616.4% 5 ALASKA AIR GROUP INC 1341.6% 18 CENTENE CORP 588.8% 6 SKYWORKS SOLUTIONS INC 1128.2% 19 SALESFORCE.COM INC 576.7% 7 TRANSDIGM GROUP INC 987.0% 20 EXTRA SPACE STORAGE INC 568.5% 8 AMAZON.COM INC 966.0% 21 ILLUMINA INC 533.2% 9 ROSS STORES INC 923.3% 22 MAIN STREET CAPITAL CORP 520.7% 10 EDWARDS LIFESCIENCES CORP 811.3% 23 SHERWIN-WILLIAMS CO/THE 499.1% 11 MASTERCARD INC - A 693.1% 24 IDEXX LABORATORIES INC 498.8% 12 CONSTELLATION BRANDS INC-A 655.8% 25 TJX COMPANIES INC 491.7% 13 CONCHO RESOURCES INC 641.3% *Note: Bloomberg data from all current constituents of the S&P 500 in existence since October 5, 2007 and assuming dividends were reinvested in each security; return analysis is through June 1, 2017 Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 26

MAIN Total Return Performance Since IPO Recessionary Period Notes: (1) Assumes dividends reinvested on date paid (2) The Main Street Peer Group includes all BDCs that have been publicly-traded for at least one year and that have total assets greater than $500 million based on individual SEC Filings as of December 31, 2016; specifically includes: AINV, ARCC, BKCC, CPTA, FDUS, FSC, FSFR, FSIC, GBDC, GSBD, HTGC, MCC, MFIN, NMFC, PFLT, PNNT, PSEC, SLRC, SUNS, TCAP, TCPC, TCRD, TICC, and TSLX (3) Main Street Peer Group is equal weighted (4) Indexed as of October 5, 2007 and last trading date is March 31, 2017 Consistent market outperformance through various economic cycles Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 27

Chad Green MAIN (2) President Steven Geuther Associate Main Street Capital Corporation Main Street Capital Corporation NYSE: MAIN mainstcapital.com

Main Street’s View of Transaction and Background Proprietary product and machinery Business: • Well-regarded business with a proprietary product and strong record Casing and tubing coating for as an industry leader downhole corrosion prevention and cement • Innovative and proprietary machinery, creating significant barriers to adhesion entry and maximizing production efficiencies Original Investment Date: Favorable transaction rationale December 2012 • MAIN provided entirety of capital required to facilitate the transaction, resulting in the family retaining control of the business Investment Type: and Main Street’s ownership percentage of approximately 49% • - Minority equity investment Allowed the first generation founder to achieve full liquidity and retire while his son (Chad Green, President) rolled the majority of his - First lien, senior secured proceeds, creating an alignment of incentives for all shareholders going forward without the family giving up control of the business debt investment Significant growth potential in domestic and international markets Transaction Type: • With a strong foothold in the Permian Basin and the addition of a Minority recapitalization to key sales manager, the Company has been able to rapidly acquire facilitate generational transfer new customers domestically given the superiority of the product and lack of viable alternatives Capital Invested: • The Company has meaningful opportunity for growth via expansion $21.4 million ($15.0 million in the Middle East and other international markets given its existing debt and $6.4 million joint venture in Oman and recently awarded joint venture in Qatar common equity) Opportunity to partner with strong existing owner / operator Main Street Capital Corporation NYSE: MAIN mainstcapital.com

Company Overview • Bond-Coat, Inc. (“Bond - Coat” or the “Company”) is an Midland, TX Headquarters industry leader in downhole, external casing and tubing coatings for corrosion prevention and cement adhesion in oil and gas drilling & production. • Headquartered in Midland, Texas, the Company began operations in 1964 with its original product, Ruff-Coat, which was designed to achieve a better wellbore cement to casing bond as well as to provide a protective coating to tanks and other oil field equipment. – Ruff-Coat has since been essentially phased out, as Flint-Coat is the primary offering. • Bond- Coat’s proprietary product used today, Flint-Coat, is Finished Product: Coated Casing a mix of epoxy and flint aggregate which includes a layer of resin, a layer of flint and a second layer of resin which is all applied after the pipe has been sandblasted using a proprietary process. • While the majority of Bond- Coat’s domestic coated pipe is utilized in the Permian Basin, the Company entered into a Joint Venture in Oman in 2010: – The Oman J.V. is owned 50% by Bond-Coat, and utilizes blasting and coating machinery built by Bond-Coat and the Flint-Coat proprietary mix. Main Street Capital Corporation NYSE: MAIN mainstcapital.com

Product Overview: Flint-Coat • Flint-Coat is a proprietary and unique product that is applied externally to oil and gas production casing to prevent downhole external corrosion. • Flint-Coat is differentiated from other similar products in the market as it can achieve corrosion resistance, abrasion resistance and cement adhesion at the same time, which are unique selling points and provide Bond-Coat significant competitive advantages. • Flint-Coat is also the cheapest solution available in the market, compared to both direct and indirect competitors, as well as other alternatives. Main Street Capital Corporation NYSE: MAIN mainstcapital.com

Downhole Casing Corrosion Overview • In the oil & gas industry, downhole external casing corrosion is an issue with which many operators have to address on a day to day basis. – Numerous production casing failures due to external corrosion have been reported in regions such as West Texas, Middle East and North Africa. • Cement failure caused by a poor cement job and ‘theft zones’ in the formation are the primary reasons potentially leading to external casing corrosion. – Casing corrosion will result not only in the loss of the casing but also the interruption of production, loss of well, or even permanent damage to the reservoir. • Nearly all causes of external casing corrosion (dissimilar metal corrosion, dissimilar soils, differential aeration, bacteria, “stray current” interference) are highly likely when the casing is attacked by saline water, resulting from a cement failure. • A significant portion of oil and gas fields worldwide are exposed to saline aquifers, especially in the US, Middle East, Far East and North Africa. – The Middle East is one area that is most significantly covered by saline aquifers and external casing corrosion is one of the most common problems with well integrity in that region. Main Street Capital Corporation NYSE: MAIN mainstcapital.com

Cement Adhesion Overview • An added benefit to corrosion control is achieved when using Flint-Coat through the production zone where No coating Flint-Coat cement is applied. – The illustration shows a common communication problem. – As oil enters the casing, some of the production can be lost to a thief zone via a micro annulus from an imperfect cement bond to untreated casing. • Another costly problem is water encroachment into the production zone. – With the cement adhering to the Flint-Coat, a near perfect bond is achieved. – Wellbore and casing become one, leaving no avenue for communication. Main Street Capital Corporation NYSE: MAIN mainstcapital.com

Flint-Coat – Coating Process 1. Surface Preparation: – New and used casing and tubing go through Bond- Coat’s automated, proprietary grit blasting machine, removing any surface contaminants and creating a rough profile to increase adhesion. 2. Coating Application: – Once the joints have been blasted, each joint is then coated with Bond- Coat’s proprietary mix of epoxy resin followed by a layer of flint aggregate. – The Flint-Coat aggregate and epoxy resin then cures in a rolling oven and a final layer of resin is applied. – The process of placing flint aggregate between two layers of resin results in a reinforced coating which is tougher than any other coating or wrap in the world. 3. Quality Control & Inspection Main Street Capital Corporation NYSE: MAIN mainstcapital.com

Proprietary Machinery & Coating Line • The Company’s proprietary sandblasting and coating machinery is custom-built and maintained in-house, creating a scalable, significant barrier to entry: – Bond-Coat can sandblast and coat several times more feet per hour than any known competitor. – The Company’s blasting and coating lines are highly scalable, enabling them to be built at its headquarters in Midland and shipped to other areas to be assembled (i.e. the Oman J.V.). Main Street Capital Corporation NYSE: MAIN mainstcapital.com

Representative Customers • Bond- Coat’s domestic and international customers represent some of the largest major and independent exploration & production companies in the industry. • These customers have proven the effectiveness of Flint-Coat through extensive field and laboratory testing. Main Street Capital Corporation NYSE: MAIN mainstcapital.com

International Growth – Recent Developments • After extensive testing and trials, Bond-Coat recently received a contract with Qatar Petroleum: – The Company is currently building additional equipment for a coating line to send to a new joint venture facility in Doha, Qatar. – Consistent with practices employed by other major, foreign oil & gas related businesses in Qatar, the Company will be forming a joint venture with Petroleum Technology Co. in Doha. – The contract is initially for $3.75 million over three years, but Bond-Coat believes the volume and additional work that will likely come from Qatar’s offshore state drilling company could potentially result in annual revenues greater than $5 million. • Bond-Coat has been in discussions to coat pipe for Saudi Aramco for several years, and has undergone extensive laboratory testing: – Bond-Coat was awarded the opportunity to participate in the final stage of required testing in Q1 2017, in which Saudi Aramco put Bond- Coat’s coated casing downhole and, after a period of 6-12 months, will run a logging tool downhole to measure or detect any corrosion. – Bond-Coat anticipates entering into a contract with Saudi Aramco by Q1 2018. Main Street Capital Corporation NYSE: MAIN mainstcapital.com

International Growth – Additional Opportunities • The Company has received significant interest from Abu Dhabi Company for Onshore Oil Operations (“ADCO”), the company responsible for over half of Abu Dhabi’s oil output, and Upper Zakum Offshore Oil Field Development, or ZADCO, a joint venture with Exxon Mobil. – ADCO is in the process of issuing a purchase order to Bond-Coat for a test trial in 2017. • The Company has also received significant interest in its product from another major operator in Abu Dhabi: the Abu Dhabi Marine Operating Company (“ADMA”) . • ADMA has issued a purchase order for a test trial to be conducted in the Oman facility. • Chad Green, Bond- Coat’s majority owner and President, has spent extensive time overseas this year for testing and additional meetings. • Statoil Petroleum expressed strong interest in Flint-Coat for drilling activities in the North Sea. • Statoil conducted a recent test comparing Flint-Coat to uncoated casing to determine the cement bonding capabilities, and had to quit mid-test as they could not remove the cement/coating from the pipe to even get a metallurgical reading, illustrating the extreme bonding capabilities of Flint-Coat. Main Street Capital Corporation NYSE: MAIN mainstcapital.com

Historical Timeline and Valuations $12 500.0% $11.2 $11.2 $10.5 $10 400.0% $10.2 $10.2 $10.2 $9.3 $9.1 $8.9 (Equity Cost and FV $ in millions) $8 300.0% $7.6 $7.5 $6.4 $6.4 $6.4 $6.4 $6.4 $6.4 $6.4 $6.4 $6.4 $6 $6.4 $6.4 $6.4 200.0% $6.2 $6.2 $6.4 $6.7 $6.4 $5.1 $5.1 $4 100.0% $2 0.0% $0 -100.0% Dec-12 Dec-13 Mar-14 Jun-14 Sep-14 Dec-14 Mar-15 Jun-15 Sep-15 Dec-15 Mar-16 Jun-16 Sep-16 Dec-16 Mar-17 Equity Cost ($) Equity Fair Value ($) EBITDA Growth % From Original Investment Date Net Debt to EBITDA as a % 2012 2013 2014 2015 2016 2017 (A) (B) (C) (D) (E) (F) (G) (H) A – Q4 2012 B – Q1 2013 C – Q2,Q3 2014 D – Q2 2015 E – Q1,Q2 2016 F – Q4 2016 G – Q1 2017 H – Q2 2017 MAIN completes Bond-Coat WTI crude spot Bond-Coat WTI crude spot Bond-Coat Bond-Coat Bond-Coat minority recap hires price: $107.95 per hires Sales price falls to substantially awarded field test awarded contract Operations barrel; US Onshore Manager, Joe $26.19 per barrel; completes its second for Saudi Aramco; with Qatar Thaggard Manager, Tom Rig Count: 1,931 US Onshore Rig automated coating coated casing Petroleum, begins Soule line in Midland currently downhole join venture Count falls to 404 for removal & formation testing in 2H 2017 Main Street Capital Corporation NYSE: MAIN mainstcapital.com

MAIN (2) Colton Braud Managing Director Main Street Capital Corporation Main Street Capital Corporation NYSE: MAIN mainstcapital.com

Main Street’s View of Transaction and Background Location 1. Family-owned and operated business with market leading position in the Greater Marietta, Georgia Atlanta Metropolitan area Business 2. Cash flow positive every year since inception in 1997 Provider of clinical respiratory and durable medical equipment for 3. Historically undercapitalized business with the majority of free cash flow being paid as pediatric patients distributions to the Company founder Website 4. Recapitalization transaction with Main Street allowed all family members to obtain partial or full liquidity and firmly positioned Kathleen Yeakey as CEO www.softtouchmedical.com 5. Talented, motivated executive ready for CEO ascension Original Investment Date October 2014 6. Longstanding relationships with the primary pediatric referral sources in Atlanta and throughout the state of Georgia Investment Type First lien, senior secured term loan 7. High barriers to entry due to accreditation process and high standard of care required Majority equity investment for pediatric patients Transaction Type 8. Recurring rental revenue drives sales of consumable / disposable products Majority recapitalization transitioning leadership of the 9. Various near- and medium-term growth opportunities through (i) opening of satellite Company to its current CEO and to distribution centers, (ii) expansion of product and service offerings and (iii) potential support growth initiatives M&A activity Capital Invested 10. Main Street provided 100% of the debt and equity capital needed to close the $15.9 million ($10.0 million debt transaction and $5.9 million equity) – 85% MAIN / 15% HMS Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 2

MAIN (2) Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 3

Company Overview Soft Touch Medical (“Soft Touch” or the “Company”) is the leading • home provider of durable medical equipment primarily serving pediatric patients across the state of Georgia. • The Company was founded in Marietta, GA, in 1997 to address the needs of the increasing amount of patients receiving home healthcare. Soft Touch carries a complete inventory of durable medical equipment • (“DME”) and many disposable supplies. • In addition to DME, the Company provides patients with enteral therapy equipment, respiratory machines and other pediatric monitors. Soft Touch is known for its outstanding customer service and quick • turnaround delivery times. • The Company offers 24/7 delivery, setup and instruction of its products and employs highly trained respiratory therapists. • The Company offers Spanish interpreters at both the technician and front office levels, allowing it to support a greater patient base. • Soft Touch operates in three locations – Marietta, GA (opened in 1997); Macon, GA (2015); and Savannah, GA (2016) – with near-term plans to expand into adjacent states. Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 4

Referral Sources • Hospitals – Working directly with the various Marietta, GA case managers at hospitals across Georgia who have autonomy when referring pediatric patients • Primary Referral Sources: • Children’s Healthcare of Atlanta • Utilized the Company’s delivery services for ~15 years • Provider of ~80% of all pediatric services in the Atlanta metropolitan area • More than 30 independent case Macon, GA Savannah, GA managers across the CHOA network • Children’s Hospital Navicent Health • Primary hospital in the Macon region with 66 beds and a growing need for in home health services • Memorial Hospital Savannah, GA • Leading children’s hospital in the fastest growing city in Georgia “At Children's [Healthcare of Atlanta], we know kids aren't simply tiny adults. They need specialized pediatric care. Our team makes sure your child is comfortable and happy while in our care. We're committed to making all kids better today and healthier tomorrow.” Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 5

Payor Mix Pre-Closing Current Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 6

Relationships with Industry Leading Suppliers Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 7

Expanded Coverage Area Long-standing relationship with four location hospital system, Children’s Healthcare of Atlanta (25 counties) Bridged the gap between northwest and southeast Georgia and facilitated a strong relationship with The Children’s Hospital Naviscent Health (30 counties) Has become the preferred pediatric DME provider at Savannah’s Memorial Hospital in less than one year and extended coverage area into South Carolina market (19 counties) Soft Touch has grown to cover the majority of the state of Georgia and has near-term plans to expand further throughout the state and into Alabama, Tennessee and South Carolina. Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 8

Product Overview – Enteral • Enteral feeding products provide patients the ability to receive necessary nutrition during treatment of temporary acute conditions or permanent chronic disabilities. Feeding Pump • Enteral feeding products provided by the Company include: • Portable feeding pumps • Feeding pump backpacks Feeding Pump Backpack • Nutrition pumps Nutrition Pump • Gastric (“G - Tube”) supplies • Nasogastric (“NG - Tube”) supplies NG-Tube Clinical Nutrition Infant Formula G-Tube Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 9

Product Overview – Respiratory Equipment & Ventilators The Company offers respiratory and • advanced respiratory care equipment. These products require significant in-home setup and education for the patient and their guardian. • Key respiratory care products include: • Oxygen systems • Concentrators • Nebulizers IPV Unit • Suction machines and pulse oximeters • Advanced respiratory care products include: Oxygen • Intrapulmonary percussive ventilators Concentrator (“IPV Units”) • Continuous (“CPAP”) and Bi -level (“ BiPAP ”) Positive Airway Pressure Cough Assist machines • Heated humidification systems BiPAP • Wireless modems for compliance Equipment • Cough assists CPAP Equipment Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 10

Product Overview – Infant Monitors & Phototherapy Soft Touch provides infant monitors that track • the respiratory systems of babies in the home. Also known as apnea monitors, these • products detect any pauses in breathing or decreases in oxygen levels. 2 PS Apnea Monitor The Company’s primary apnea monitor • products include: • Smart Monitor II – a lightweight portable monitor that sounds an alarm upon any respiratory changes and records up to 2 MB of memory to document patient conditions for an extended period of time Smart Monitor II • 2PS Apnea Monitor – a detector of heart rate, oxygen level and respiration changes in a patient primarily used to document patient responses to sedation and treatment Bilibeds provide intensive phototherapy for • newborn jaundice. Bilibed for Jaundice Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 11

Product Overview – Durable Medical Equipment • Pediatric durable medical equipment supports patients’ manual and powered movement around the home. Pediatric wheelchairs are designed to fit • smaller body weights and sizes than traditional wheelchairs. Commode Chair Folding Walker Other DME products include: • • Walkers • Crutches • Beds • CPM • Bathroom safety equipment Pediatric Wheelchair Four-Wheel Rotator • Transfer aids Larger DME is typically provided as rental • equipment and is offered as a complementary product to other respiratory and enteral equipment and supplies. Transfer Aids Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 12

Patient Case Study - Keegan “You never think that you are going to have a special needs child. On the same day that we discovered we were to have a son we were told he had something called an Omphalocele. It is an abdominal wall defect. We had no idea what life would be like after he was born. Once he was born he was immediately intubated. Meaning he had to have a breathing tube put down his throat and into his lungs. He was on O2 and had a feeding tube. After being in the NICU for 2.5 months my husband and I decided to have our son trached and we saw his handsome face for the first time. We went home for the first time in August of 2014. He was born in March 2014. We went home in an ambulance with the most amount of machines that any patient could go home with. We were petrified!!! Soft Touch was not the first company we had, but once we switched it made a world of difference. We could call and always get an answer or a call back with an “Soft Touch was not the first answer. We love the company and what they stand for. Soft Touch is all company we had, but once we about the patient and what he or she needs. If we run out of O2 it would be switched it made a world of difference. We could call and delivered that same day or first thing the following morning. If we lose a always get an answer or a call trach they mail us another. If we discover that we do not need something in back with an answer. We love our monthly order they discontinue it with no questions asked. the company and what they stand for. Soft Touch is all Having a medically fragile child is difficult enough, yet having a company about the patient and what he that provides what your child needs makes it much easier to bear .” or she needs.” - Alison P. Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 13

MAIN Historical Timeline and Valuations $10 300.0% $9.2 $9.2 $8.7 $8.6 $8 Equity Cost and FV ($ in millions) $7.5 200.0% $5.7 $5 $5.3 $5.0 $5.0 $4.9 $4.9 $4.9 $4.9 $4.9 $4.9 $4.9 $4.9 $4.9 100.0% $3 $0 0.0% Dec-14 Jun-15 Sep-15 Dec-15 Mar-16 Jun-16 Sep-16 Dec-16 Mar-17 Equity Cost ($) Unrealized Appreciation EBITDA Growth % From Original Investment Date Net Debt to EBITDA as a % Q3 2014 Q3 2015 Q3 2016 Main Street, HMS and New location New location opened in management complete opened in Savannah, GA, expanding the Company’s coverage recapitalization of Soft Macon, GA Touch for $15.9 area into South Carolina million Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 14

Lower Middle Market Equity June 2017 Main Street Capital Corporation NYSE: MAIN mainstcapital.com Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 1

Conservative Historical Nature of MAIN’s Valuations for Equity Investments Exits of LMM equity investments resulting in realized gains have compared positively to previously recorded fair values – Exits of 27 LMM equity investments with realized gains have resulted in total realized gains of $167 million Two Quarters Prior Four Quarters to Exit Prior to Exit Realized Value at Exit in Comparison to Prior Qtr FV 126% 170% Realized Value at Exit in Excess of Prior Qtr FV $43,277 $87,244 ($ in 000's) MAIN valuation approach and key inputs – Market-comparable/Historical cash flow approach • Based on actual MAIN entry transaction multiples, as adjusted over time for overall market and specific company changes • MAIN EBITDA valuation multiples compare favorably to industry and market valuations: EBITDA Multiple 7.1x MAIN Weighted Average (1) MAIN Median (1)(2) 6.0x 7.8x Other BDC’s – All Equity (3) Industry (4) 8.1x to 8.5x – Discounted cash flow (DCF) approach • Weighted average cost of capital (WACC) – significant component of DCF approach is significantly impacted by industry and overall market factors • These WACC components are obtained from third party sources and can fluctuate significantly from quarter to quarter (1) Source: March 31, 2017 Form 10-Q filing MAIN’s median EBITDA multiple represents the median EBITDA multiple for all equity investments, except investments for which the valuation does not include use of an EBITDA multiple. (2) (3) As published in the most recent Form 10-K or Form 10-Q filed by each BDC as of May 17, 2017. Other BDCs includes 35 BDCs and includes weighted average EBITDA multiples for all forms of equity investments. (4) Source: Overview of Lincoln International Valuations & Opinions Group dated May 2017 as published by Lincoln International. Multiples represent the Total Enterprise Value / Adjusted EBITDA for the Last 12 Months as of December 31, 2016 for all transactions with Total Enterprise Values between (i) $10 million and $30 million (8.1x) and (ii) $30 million to $50 million (8.5x) Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 2

MAIN LMM Strategy Produces Differentiated Returns to Investors Net Unrealized Appreciation of ~$2.91 per share, or $161 million, from LMM equity investments (1) – Portfolio diversity has resulted in LMM equity investment appreciation across a diverse group of portfolio companies and industries (As of March 31, 2017) With Unrealized With Unrealized Appreciation Depreciation % of LMM companies with MAIN Equity Investment 63% 24% Number of LMM companies with MAIN Equity 45 17 Investment – Remaining Net Unrealized Appreciation at March 31, 2017 is after $84 million of realized gains on the exits of 4 LMM equity investments since December 31, 2015 Equity Exits Enhance MAIN’s Portfolio Returns (2) – LMM equity exits have enhanced MAIN’s portfolio returns and provided significant upside, in addition to offsetting the inevitable credit losses occurring from non-investment grade debt investments • Exits of 27 LMM equity investments resulted in realized gains of $167 million • Exits of 4 LMM equity investments in 2016 and Q1 2017 resulted in realized gains of $84 million • Exits of 15 LMM equity investments resulted in realized losses of $15 million • Net realized losses on exits and restructurings of LMM debt investments of $33 million • Net realized losses on exits and restructurings of non-LMM debt and equity investments of $43 million • Cumulative net realized gains across all investment portfolios of $76 million (1) As of March 31, 2017 (2) Includes all full exits of LMM equity investments since Initial Public Offering in October 2007 through March 31, 2017 Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 3

Middle Market Update June 2017 Main Street Capital Corporation NYSE: MAIN www.mainstcapital.com Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 1

Middle Market Debt Investment Strategy Middle Market Credit Opportunities Private Loans Description Generally investments in first Strategic investments in the Proprietary investments lien secured loans through secondary market, originated through strategic primary loan issuance opportunistic purchases, relationships with other special situations. Investments investment funds on a in Credit Opportunities will collaborative basis with generally be included in the attractive risk/return Middle Market portion of characteristics MAIN’s investment portfolio. • First lien secured debt • First lien secured debt and • Primarily first lien secured Targeted • Floating rate high yield bonds debt Investments • Majority have a B or higher • Ratings agnostic • Primarily floating rate S&P rating instruments • Unrated Targeted 6-10% gross yields 8-12% gross yields 7-10% gross yields Returns Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 2

Middle Market Assets 1 AUM by Fund Spread by Product L+400 $2,000 I-45 I-45 L+500 $1,600 I-45 I-45 L+600 $ AUM (Millions) $1,200 HMS HMS HMS MAIN L+700 $800 HMS HMS HMS L+800 $400 MAIN MAIN MAIN MAIN MAIN L+900 2013 2014 2015 2016 1Q '17 (1) Middle Market only; amounts at fair value Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 3

Portfolio Statistics 1, 2 Portfolio Credit Statistics 5.00x $125.0 $98.8 $98.6 4.50x $100.0 $95.5 $94.1 $94.2 $79.0 $77.2 4.00x $75.0 $68.8 3.97x 3.94x 3.84x 3.82x 3.52x 3.50x $50.0 3.50x 3.41x 3.47x 3.42x 3.35x 3.37x 3.31x 3.27x 3.15x 3.11x 3.07x 3.00x $25.0 2.50x $0.0 Q4:13 Q2:14 Q4:14 Q2:15 Q4:15 Q1:16 Q4:16 Q1:17 Portfolio Average EBITDA Portfolio Average Total Net Leverage Ratio Portfolio Average Interest Coverage Ratio (1) Middle Market held by MAIN (2) Leverage and interest coverage statistics include only borrowing base eligible assets which excludes second lien and other non-eligible assets. Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 4

Consistent Asset Mix 1 Portfolio Asset Mix 1.8% 0.9% 1.9% 0.7% 0.7% 100% 6.0% 9.9% 10.1% 9.8% 10.8% 90% 80% % of Total Portfolio (at Fair Value) 70% 60% 50% 93.1% 89.4% 89.2% 88.4% 87.4% 40% 30% 20% 10% 0% 2013 2014 2015 2016 1Q '17 First Lien Second Lien Unsecured (1) Represents Middle Market and Private Loans managed by Middle Market investment team held by MAIN Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 5

Middle Market Returns LTM Total Returns 1 vs. Indices 15.00% 13.96% 13.00% 12.12% 11.00% 10.39% 10.31% 9.23% 8.86% 9.00% 7.09% 6.84% 7.00% 5.72% 4.91% 4.72% 5.00% 3.46% 3.00% 1.95% 1.38% 1.00% 2013 2014 2015 2016 Q1: 2017 -0.19% -1.00% MAIN Middle Market² S&P/LSTA U.S. Middle Market Index CS Leveraged Loan Index - B Ratings (1) Total return includes interest, fee and dividend income plus realized and unrealized gains (2) Represents Middle Market and Private Loans managed by Main’s Middle Market investment team held by MAIN Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 6

Credit Selection History 1 Cumulative Since Inception of MAIN As of 3/31/2017 Middle Market Group ($ in millions) (Q2:2009 – Q1:2017) Cost / # of Companies Cost / FMV ~$2,300 / ~300 $588.9 / $568.8 Investments $62.1 / 9 $31.6 / $28.3 Defaults 2 58.3% 89.3% Recovery 3 (1) Middle Market assets held by MAIN (2) Includes investments placed on non-accrual plus one distressed credit sale (3) Realized value on defaulted exited investments plus FMV as of 3/31/17 for current investments. Recovery does not include interest income. Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 7

Default Rates LTM Default Rates 4.00% 3.50% 3.43% 3.50% 3.24% 3.00% 2.82% 2.50% 2.37% 2.25% 2.11% 2.11% 2.06% 2.05% 2.00% 2.00% 1.58% 1.61% 1.56% 1.50% 1.43% 1.50% 1.21% 1.00% 0.50% 0.00% 0.00% 2013 2014 2015 2016 Q1: 2017 Average 2013 - 2016 MAIN Middle Market¹ S&P/LSTA U.S. Middle Market Index S&P/LSTA U.S. Index² (1) As a percentage of cost of Middle Market assets held by MAIN (2) Includes loans not tracked in the LSTA/LPC mark-to-market service Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 8

Benefits of Middle Market to MAIN • Return on Equity – Exceeds MAIN monthly dividend • Asset Management Business – Facilitates additional return for MAIN without deploying capital • Treasury Function – Repayments provide funding in any market • Leverage / Debt Structure – Credit facility would be different without marked assets • Diversity of Markets – Ability to pivot between LMM, PL, and MM • Market Color – Relationships Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 9

This is neither an offer to sell nor a solicitation to buy the securities of HMS Income Fund. An offering is made only by the prospectus. No offering is made in the state of New York in connection with any offering. Neither the Securities and Exchange Commission, the Attorney General of the State of New York nor any other state securities commission has approved or disapproved of these securities or determined if the prospectus is truthful or complete. Any representation to the contrary is a criminal offense. FOR INSTITUTIONAL USE ONLY. Not for distribution to the public. Hines Securities, Inc., Member FINRA, SIPC, is the dealer manager. 5/17

Historical Capital Raise Cumulative Gross Proceeds Since Inception 1 $800 Gross Capital Offering Period $732 Raised ($M) $707 $683 $700 Initial Offering $656 $601 (closed 12/1/15) $601 $622 Follow-on Offering Through 3/31/17 $600 131 (opened 1/5/16) $538 Inception through 3/31/17 $732 $500 $474 $394 $M $400 $295 $300 $205 $200 $134 $81 $100 $42 $21 $12 $4 $1 $0 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 2012 2013 2014 2015 2016 2017 1 Includes DRIP proceeds. FOR INSTITUTIONAL USE ONLY. Not for distribution to the public. Hines Securities, Inc., Member FINRA, SIPC, is the dealer manager. 5/17

Portfolio Composition Asset Class Detail as of 3/31/17 ($M) % of Portfolio % First Lien of Weighted Average Asset Class Fair Market Value Portfolio Companies Total Debt Effective Yield 1 Middle Market Debt $573.4 59.8% 64 81.6% 8.8% Private Loan Debt 231.9 24.2% 31 94.9% 9.1% Lower Middle Market 82.3 8.6% 23 95.3% 11.9% Debt Middle Market Equity 4.2 0.4% 4 - - Private Loan Equity 2 5.7 0.6% 7 - - Lower Middle Market 40.7 4.2% 23 - - Equity 2 Other 20.9 2.2% 3 - - 124 3 Total $959.1 100% 86.4% 8.9% Portfolio holdings are subject to change. 1 Weighted average effective yield is calculated based on HMS Income Fund’s investments as of March 31, 2017 and includes accre tion of original issue discounts and amortization of premiums, and the amortization of fees received in connection with transactions. Investments on non-accrual status are assumed to have a zero yield in the calculation. 2 Includes warrants. 3 Represents the number of unique portfolio companies. The number of unique portfolio companies is less than the sum of the individual asset class figures because HMS holds both debt and equity investments in select portfolio companies. Data based on fair market value as of March 31, 2017. FOR INSTITUTIONAL USE ONLY. Not for distribution to the public. Hines Securities, Inc., Member FINRA, SIPC, is the dealer manager. 5/17

3/31/17 Portfolio Highlights  118 Debt Portfolio 124 Portfolio Aggregate Fair $959.1M  34 Equity Issuers 1 Market Value  3 Other First Lien Debt Weighted Avg. as % of Effective Yield 86.4% 8.9% Total Debt on Investments (Unlevered) 2 Fair Market Value 1 Portfolio holdings are subject to change. 2 Weighted average effective yield is calculated based on HMS Income Fund’s investments as of March 31, 2017 and includes accre tion of original issue discounts and amortization of premiums, and the amortization of fees received in connection with transactions. Investments on non-accrual status are assumed to have a zero yield in the calculation. FOR INSTITUTIONAL USE ONLY. Not for distribution to the public. Hines Securities, Inc., Member FINRA, SIPC, is the dealer manager. 5/17

3/31/17 Portfolio Highlights (cont’d) 46 Sectors Top Five Sectors by FMV: Media 8.4% Industry Weighted Avg. Hotels, Restaurants & Leisure 8.3% B Diversification 1 Credit Rating 2 Commercial Srvcs. & Supplies 8.1% Construction & Engineering 6.1% IT Services 4.1% Top Five Total 35.0% 41% Investments on 3/31/17 Debt ($M): Non-Accrual Capacity $480) Leverage 1.1% as % of Less: Borrowings (386) Fair Market Value Availability $94) L+275 3 Cost of Capital 1 Portfolio holdings and business sector diversification are subject to change. 2 Approximately 45% of the portfolio maintains an S&P credit rating. 3 Represents borrowing cost under HMS Income Fund’s credit facilities as of March 31, 2017. Data based on fair market value as of March 31, 2017. FOR INSTITUTIONAL USE ONLY. Not for distribution to the public. Hines Securities, Inc., Member FINRA, SIPC, is the dealer manager. 5/17

Net Asset Value Per Share 2012 - 3/31/17 $9.00 $8.91 $8.86 $8.86 $8.85 $8.79 $8.69 $8.75 $8.57 $8.50 $8.40 $8.35 $8.25 $8.16 $8.15 $8.00 $7.92 $7.88 $7.77 $7.75 $7.67 $7.50 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 2012 2013 2014 2015 2016 2017 FOR INSTITUTIONAL USE ONLY. Not for distribution to the public. Hines Securities, Inc., Member FINRA, SIPC, is the dealer manager. 5/17

Total Return Comparison Q3 2012 – Q1 2017 6.0% 5.1% 5.0% 4.2% 4.1% 4.0% 3.6% 3.4% 3.4% 2.9% 3.0% 2.4% 3.2% 2.2% 2.9% 3.1% 2.0% 1.9% 1.5% 2.0% 1.4% 2.3% 1.3% 1.2% 2.1% 2.1% 1.5% 1.7% 1.0% 1.4% 1.4% 1.2% 1.2% 1.1% 0.7% 0.0% 0.2% (0.5%) (0.5%) (0.5%) (1.0%) (1.4%) (2.0%) (1.9%) (2.1%) (2.4%) (3.0%) (3.5%) (4.0%) Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 2012 2013 2014 2015 2016 2017 HMS Total Return S&P LSTA Total Return FOR INSTITUTIONAL USE ONLY. Not for distribution to the public. Hines Securities, Inc., Member FINRA, SIPC, is the dealer manager. 5/17

MAIN’s Asset Management Business Fee Structure  MAIN 1 Base Management Fee – 1%  MAIN 1 Incentive Fee – 10% Benefits to MAIN  No significant increases to MAIN’s operating costs  Utilize existing infrastructure and leverage fixed costs  No invested capital  Monetize the value of MAIN franchise  Impact on MAIN’s financial results:  $7.9 million to NII 2 for 2016  $2.2 million to NII 2 for 1Q2017  $33.5 million of Cumulative Unrealized Appreciation as of 3/31/17 1 Through MAIN’s wholly owned unconsolidated subsidiary, MSC Advisor I, LLC 2 Contribution to Net Investment Income includes (a) dividend income received by MAIN from MSC Advisor I, LLC and (b) operating expenses allocated from MAIN to MSC Advisor I, LLC FOR INSTITUTIONAL USE ONLY. Not for distribution to the public. Hines Securities, Inc., Member FINRA, SIPC, is the dealer manager. 5/17

I-45 Senior Loan Fund June 2017 Main Street Capital Corporation NYSE: MAIN mainstcapital.com Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 1

I-45 Senior Loan Fund Joint Venture formed between MAIN and Capital Southwest 1 I-45 SLF is a stand alone entity with a separate • Fund invests primarily in 1 st lien middle market loans Board of Directors and is accounted for as a • Total Equity Commitment of $85 million portfolio company – MAIN = $17 million = 20% – CSWC = $68 million = 80% Utilizes a 50/50 Joint • Profit distribution split: Venture voting structure as seen with other BDCs – MAIN = 24.4% – CSWC = 75.6% Created in September Benefits to MAIN 2015 • Attractive levered equity returns • “Toe in the water” of Senior Loan Funds • 22% IRR from Launch to 3/31/17 – 10-12% long term levered yield target (1) Capital Southwest Corporation (NASDAQ: CSWC) Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 2

I-45 Senior Loan Fund 1 Current Portfolio 2 • $221.8mm of Assets – $130.0mm of Debt Outstanding – MAIN has $16.2mm of Equity Invested – ~95% of Committed Equity funded • 49 Issuers • 95.2% 1 st Lien • 3.5x Weighted Average Leverage • $82.1mm Weighted Average EBITDA Deutsche Bank Leverage Facility • $165mm Revolver • 5-year term with 2 year revolving period • L+275 • Non mark to market • 66% Max Total Advance Rate (Debt to Assets) (1) Charts as of December 31, 2016 (2) As of May 16 th , 2017 Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 3

Dale Ford Chief Executive Officer Dwayne L. Hyzak President & Chief Operating Officer Main Street Capital Corporation Main Street Capital Corporation NYSE: MAIN mainstcapital.com

Main Street’s View of Transaction and Background Location Strong market position and reputation Mountain View, California With a 20-year history as a value-added reseller (“ VAR ”) of engineering design and manufacturing software and other  solutions, Hawk Ridge Systems, LLC and HRS Services, ULC (together “ Hawk Ridge ,” or the “ Company ”) has developed a Business strong relationship with its most significant vendor, Dassault Systems (“ Dassault ”), the publisher of SolidWorks, the world’s Value-added reseller of leading 3D computer-aided design (CAD) software, and a full suite of other product lifestyle management (PLM) tools. engineering design and Hawk Ridge currently accounts for ~12% of SolidWorks’ North American revenues and is viewed by Dassault’s  manufacturing software management as a leader among its VAR peers. Five times named the world’s top SolidWorks reseller, Dassault often and solutions considers Hawk Ridge first when bringing new opportunities to market. Website High quality products delivered to a highly diversified customer base www.hawkridgesys.com Hawk Ridge serves 16,000+ customers across a variety of industries, including blue-chip accounts like Google, Apple,  Original Investment Date Tesla, Medtronic and Microsoft, with the top customer contributing <2.0% of revenues. December 2016 Top-tier customer service through a scalable platform Investment Type Hawk Ridge provides customer service and support at a level beyond other VARs, providing classroom-style and online  First lien, senior secured loan training, a database of “How To” videos, real-time remote assistance, analysis consulting and rapid prototyping services. Minority equity investment Feedback received during Main Street’s due diligence process indicated that customers were particularly pleased with the  depth of technical knowledge, professionalism and responsiveness of Hawk Ridge’s employees. Transaction Type Minority recapitalization Significant growth opportunities structured to transition Dale Due to its geographic coverage and the scale of its sales and support team, Hawk Ridge is capable of achieving significant  Ford, the CEO and minority growth in its core CAD solutions and maintains the opportunity to sell various other PLM tools into its existing customer base. equity owner, into the majority Given its historical success completing acquisitions and its desire for continued future growth, Hawk Ridge’s management  ownership position and team is actively pursuing acquisition opportunities which will allow for significant synergies to be realized due to the provide full liquidity to inactive established infrastructure already in place at Hawk Ridge. equity owners Capital Invested Alignment with motivated, highly skilled and experienced CEO $16.75 million ($12.5 million Main Street structured a flexible transaction that allowed for the transfer of ownership control from the Company’s two  debt and $3.75 million equity) inactive equity owners to Dale Ford, the Company’s highly motivated CEO. Ford reinvested 100% of his value from the – 80% MAIN / 20% HMS transaction and is fully aligned with Main Street as the Company’s majority equity owner. Main Street Capital Corporation NYSE: MAIN mainstcapital.com

Company Overview • Hawk Ridge is one of North America’s leading providers of engineering design and manufacturing solutions and professional services – One of the largest and most efficient sales and marketing organizations, with 180 professionals located across 16 offices throughout the Western U.S. and Canada • Offering highly technical, widely recognized and acclaimed solutions – CAD, CAM, CAE software, and 3D printing solutions from market leading vendors like Dassault, Geometric, 3D Systems and HP • Leveraging deep technical expertise and talent to provide solutions to a diverse and impressive base of 16,000+ customers Market Leading Vendors Value-Added Reseller Diverse and Marquee Customers • • • Market leading software & technology Sales, customer support and services 16,000+ Enterprise & SMB customers • • vendors Provide CAD, CAM and CAE software, Diverse range of end markets • • Demonstrated ability to onboard and 3D printing and other solutions Blue-chip customer base with numerous • ramp new vendors 180 top-tier technical, sales and Fortune 100 strategic accounts • Receive and reject constant inquiries for marketing professionals • new vendor additions 16 offices in Western U.S. and Canada • Deep product and end-market expertise 4

A history of growth Acquisitions New Products Organic Expansion Sales Year • Founded as a provider of Parametric Technology Corp. (PTC) software solutions 1996 1998 SolidWorks (Dassault) #1 – So. California 1999 Oregon 2000 CosmoWorks (now Simulation) Washington 2001 Workgroup PDM (Dassault) 2002 Nevada #2 – No. California 2004 #3 – Nevada 2006 Enterprise PDM (Dassault) #4 -- Northwest US British Columbia 2008 Composer (Dassault) #5 – Alberta $30 Million 2011 Ontario 2012 CAMWorks (Geometric) & Electrical (Dassault) $40 Million 2013 #6 -- Manitoba 3D Systems, Simulia (Dassault) & HawkWare $50 Million 2014 $60 Million 2016 Altium / SolidWorks PCB & xBOM (HawkWare) • Added HP as a 3D printing vendor in May 2017 $75 Million 2017 • Company positioned for continued future growth 5

Serving large, high-growth markets Hawk Ridge serves some of the fastest growing design automation markets and will continue to experience strong, long-term growth as a result of these market dynamics. Engineering Software 3D Printing • • The 3D printing / additive manufacturing market The engineering software market was a is expected to rapidly expand from $3.1B in $20.0B industry in 2014 and is expected to 2013 to $21.0B in 2020 grow at an annual rate of 12.2% over the next • eight years to $50.4B in 2022 The industry is exploding and is driven by new • Hawk Ridge’s primary segments (CAD, CAM applications in attractive end markets, lower price points for consumer access, and promise and CAE) represent $15.3B of $20.0B market of mass production for commercial firms $60.0B $25.0B $50.4B $21.0B $44.8B $50.0B $20.0B $39.9B $35.6B $40.0B $20.0B $22.4B $25.2B $28.2B $31.7B $15.0B $12.8B $30.0B $10.0B $20.0B $10.0B $5.0B $3.1B $0.0B $0.0B 2014 2015 2016 2017 2018 2019 2020 2021 2022 2013 2018 2020 CAD CAE CAM AEC EDA 6

Diversified customer base • Hawk Ridge maintains a highly diversified base of over 16,000 customers – No end market accounts for more than 18.0% of all accounts • The Company has limited customer concentration – Largest customer in 2016 accounted for less than 2.0% of total sales and the top ten customers represented less than 8.0% • Approximately 1,000 customers are considered “strategic accounts”, possessing at least five 3D CAD licenses – Strategic accounts comprise 50% of renewal sales and renew at nearly 100% Consumer Energy Healthcare Industrial Technology 7

Relationships with leading vendors • Hawk Ridge offers a diverse range of solutions from market leading vendors – Core vendors are expanding and taking share from competitors • Strong, long-established relationships with its vendors % Hawk Ridge Length of Vendor Annual Sales Products Sales Relationship $3B+ ~85.0% 20 Years 3D Printers & $650M+ ~5.0% 4 Years Materials Established 3D Printers & $50M + 0.0% Feb 2016 Materials Established May 3D Printers & $48B+ 0.0% 2017 Materials $188M+ ~2.0% 4 Years $60M+ ~8.0%* 5 Years * Includes sales from services and training provided by Hawk Ridge 8

A long-tenured relationship with Dassault Key Area Relationship Overview • Dassault ascribes significant value to its VAR community, providing a favorable revenue sharing arrangement relative to those of other software vendors • Revenue sharing arrangements have been altered only once in Hawk Ridge’s Revenue Sharing 20-year history with Dassault, and Hawk Ridge does not believe this agreement will be revised again due to the time / energy to implement and reseller community pushback • Dassault has been supportive of continued consolidation among the VAR community • Acquisitions Dassault frequently presents Hawk Ridge with acquisition opportunities of other resellers and has historically financed acquisitions for the Company • Dassault has a right to approve all changes in ownership • Hawk Ridge owns the customer relationship exclusively Customer • SolidWorks does not sell direct to customers and has utilized this 100% Interaction indirect model since its inception • Hawk Ridge has free reign to expand its portfolio and offer complementary Product solutions to its customers Expansion • Dassault would disapprove of Hawk Ridge offering competing CAD solutions 9

SolidWorks #1 global value-added reseller • Hawk Ridge is the largest North American SolidWorks value-added reseller – Accounts for ~5% of global SolidWorks revenue / ~12% of North American revenue • The Company is the best recognized, awarded and regarded SolidWorks VAR – Top SolidWorks Reseller five times worldwide, twelve times in North America • Sterling reputation of customer service and support – Known for technical sophistication and client focus; 84 dedicated technical professionals Continuous Recognition as the Leading Provider of SolidWorks Solutions SolidWorks World Award Number of Wins Top Reseller – SolidWorks Worldwide 5 Top Reseller – SolidWorks North America 12 Top Reseller – SolidWorks Multi-Product Bookings Worldwide 1 Top Reseller – SolidWorks Multi-Product Licenses Worldwide 1 Top 5 Reseller – SolidWorks Bookings Worldwide 2 Top 5 Reseller – SolidWorks Multi-Product Bookings Worldwide 1 Top 5 Reseller – SolidWorks Multi-Product Licenses Worldwide 1 100% Club – Research Licenses 2 President’s Club 15 10

Wide suite of SolidWorks solutions Enterprise 3D CAD Simulation Composer Electrical PCB PDM Year 1998 2000 2006 2008 2012 2016 Adopted 3-Year 8% - 12% 12% - 15% 17% - 22% 10% - 15% 25% - 40% N/A CAGR Software Simulation Comprehensive PDM software Software enables software for Software 3D product providing a enabling the collaborative testing product Enables design software secure design and multi-line and designs in Electrical Overview enabling end-to- database for production of single line virtual Engineers to end product accessing and visual technical electrical environments design Printed design sharing design communication system prior to Circuit Boards capabilities files deliverables schematic manufacturing design Key customer Significant Significant Key customer Large area of retention Enabler of key growth growth acquisition opportunity, solution growth trends Notable opportunity Opportunity solution, highly limited relative (nearly 100% such as similar to 3D Similar to 3D Highlights recognizable and historical focus renewal paperless CAD a CAD a decade well-known on this solution among PDM manufacturing decade ago ago. customers) 11

Selling complementary products • In addition to SolidWorks, Hawk Ridge provides a range of complementary software solutions to its customers • The Company has experienced strong traction with the introduction of these offerings to date and believes there is significant runway ahead for these solutions Year 3-Year Product Vendor Description Adopted CAGR Complete computer-aided 2012 12% - 15 % manufacturing and machining software suite Advanced simulation software suite 2013 30%-40%* used to perform complex analyses with advanced physics Proprietary software to increase efficiency when working within 2011 N/A SolidWorks 3D CAD and Enterprise PDM systems * 2-Year CAGR 12

Training and services • Hawk Ridge provides training and other services that are complementary to its software and 3D printing solutions • The Company has invested substantial resources to scale these offerings – Expect high-margin training revenue stream to grow 50% in 2017 Service Overview • Training courses for both new and experienced users to help them get the most Training out of their software investment • On-demand CAD development, review and assistance for clients needing to CAD temporarily leverage a deep bench of engineering talent • PDM implementation, data migration and custom programming services to PDM optimize client PDM processes • On-demand analysis consulting services from a knowledgeable team bringing Analysis Consulting best practices and proven methodologies for design challenges • Customized API Custom API development and assistance services for industry specific Development applications which utilize parametric design and analysis • In-house rapid prototyping services providing access to a broad range of Rapid Prototyping technologies 13

Talented management team • Hawk Ridge possesses an experienced and energized management team which has driven impressive growth at the Company over the past five years • The senior leadership team consists of five executives with an average of 18+ years of experience in their respective fields • Together since 2012, Hawk Ridge’s executives have a combined 45+ years of tenure with the Company and are deeply committed to its success High Quality Senior Leadership Team Name & Title Hawk Ridge Tenure Relevant Experience Dale Ford, President & Chief Executive Officer 20 years 24 years Chief Revenue Officer 9 years 15 years Vice President of Marketing 7 years 26 years Corporate Controller 3 years 21 years Vice President of Engineering 11 years 14 years 14

Accelerate growth in existing geographies • Hawk Ridge is driving strong growth in Hawk Ridge 3D CAD Market Share 3D CAD within its existing geographies 19.5% 18.5% • 17.5% Track record of expanding 3D CAD 16.0% 15.0% 13.9% market share at a rate nearly 2x the 10.9% market average • Tremendous potential remains within the Company’s existing territories – 85,000+ potential 3D CAD additions 2012A 2013A 2014A 2015A 2016E 2017P 2018P 2016A • Driving demand are several key trends: 3D CAD Additions by Trend – 2D CAD Replacement – 3D CAD Replacement 2015 2019P New Repeat New Repeat – 3D CAD Startups Total Total Acct. Deal Acct. Deal – Existing Accounts 2D CAD Replacement 32% 12% 44% 20% 10% 30% 3D CAD Replacement 4% 12% 16% 9% 17% 25% 3D CAD Startups 20% 0% 20% 25% 0% 25% Existing Accounts 0% 20% 20% 0% 20% 20% 15

Capture new territory • SolidWorks VAR market is primed for Existing Market Expansion Opportunity consolidation – Fragmented market, aging owners and a similar model across businesses – Dassault is supportive of acquisitions made by its high-performing VARs • Hawk Ridge has held discussions with numerous potential acquisition targets to allow for geographic expansion, several of which are described below Target Geographies Served Est. Sales Company A Expansion Markets $25M Company B Expansion Markets $45M Company C Existing Markets $10M Company D Existing Markets $3M Company E Expansion Markets $50M Company F Mixed $35M Company G Mixed $10M 16

Penetrate 3D printing market • 3D Printing Projections 3D printing is expected to grow at a 30%+ CAGR over the next 7 years $15.0M – Hawk Ridge expects to reach $10.0M $15M in 3D printing sales by 2019 • Solutions are complementary to Hawk $5.0M Ridge’s software offerings; most 3D $0.0M printing customers have at least one 2015 2016A 2016E 2017P 2018P SolidWorks license 3D Printing Center • Opportunity to earn recurring revenue from material sales and service contracts in addition to new machine sales • Hawk Ridge recently invested in a state-of-the- art 3D printing center to showcase these products (pictured at right) • Other long-term opportunities include 3D print services and 3D printer leasing 17

The cutting edge of 3D printing technology • Historically, Hawk Ridge offered 3D printers and consumables manufactured by 3D Systems and Markforged, two leading vendors in the 3D printing / additive manufacturing market • However, in 2017, the Company was approached by HP to be a cornerstone in its newly- developed reseller channel for the distribution of HP’s newly developed and cutting edge 3D printing technology, which offers customers: – Superior, consistent output quality with extreme dimensional accuracy and optimal mechanical properties – Breakthrough speed (up to 10x faster than other printers on the market) – Lowest cost-per-part metric opens doors to short-run manufacturing • Acknowledging the value of the technology, the brand and HP’s reputation, Hawk Ridge accepted as a HP 3D printing solutions reseller in May 2017 • The Company also offers its customers installation, training, next-day support services and market- leading applications expertise to help customers optimize their 3D printer performance, throughput, part quality and yield 18

Capital Structure June 2017 Main Street Capital Corporation NYSE: MAIN mainstcapital.com Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 1

Our Capital Structure (1) 100% Maintain a conservative capital structure $2,250 • Utilize equity offerings for the majority of our capital financing 90% Moderate- • Maximize access to beneficial Small Business Investment term $2,000 Capital 80% Company (SBIC) Debentures • Opportunistically add other long-term debt financing options $1,750 70% • Maintain a significant revolving credit facility to provide liquidity Long-term $1,500 between long-term debt and equity financings 60% Capital (in millions) • Maintain significant liquidity and maximize duration of debt $1,250 maturities 50% $1,000 Match capital structure with investment assets 40% • Duration $750 30% • Fixed vs Floating Permanent Capital $500 20% Use conservative leverage to enhance shareholder returns • Total Debt to NAV of 0.64x as of March 31, 2017 (2) $250 10% • Total Debt, excluding SBIC debt, to NAV of 0.45x as of March 31, 2017 (2) $- 0% • Weighted average yield (3) on existing investment portfolio of RLOC Unfunded Capacity RLOC 5-Year Notes 10-Year Notes 10.1% vs weighted average cost of debt (4) capital of 4.2% SBIC Unfunded Capacity SBIC Debentures Equity (1) As of March 31, 2017 (2) Calculated based upon the par value of debt (3) Weighted Average Yield calculated using the effective interest rates for all debt investments at cost as of March 31, 2017, including amortization of deferred debt origination fees and accretion of original issue discount but excluding fees payable upon repayment of the debt instruments and any debt investments on non-accrual status (4) Weighted Average Cost of Debt calculated utilizing stated interest rate of debt capital and including amortization of deferred financing costs Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 2

Long-term Duration of Debt Obligations 400 MAIN’s conservative capital structure 350 provides long-term $40.0 access to attractively- 300 priced and structured 250 debt facilities (in millions) • 200 Allows for investments in assets with long- 150 term holding periods / $288.0 illiquid positions and $175.0 100 greater yields and Internally Externally overall returns Managed Managed $90.7 50 BDC’s (3)(5) BDC’s (4)(5) MAIN (2) • $63.8 Provides downside $55.0 $40.4 $5.0 $20.0 $16.0 protection and liquidity 0 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 through economic cycles (1) (2) (3) Credit Facility SBIC debentures 6.125% Notes 4.50% Notes • Allows MAIN to be (1) Based upon outstanding balance as of March 31, 2017; total commitments at opportunistic during March 31, 2017 were $555.0 million periods of economic (2) Issued in April 2013; redeemable at MAIN’s option beginning April 2018 uncertainty (3) Issued in November 2014; redeemable at MAIN’s option at any time, subject to certain make whole provisions Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 3

Match Funding with Investment Assets (1) 100% Main Street maintains a Moderate- 90% term Capital capital structure that is designed to match our 80% Moderate- capital funding with our term / partially investment assets Long-term 70% illiquid Capital Investments • The term of our capital 60% sources is matched (% of total) with the expected hold 50% period of our portfolio 40% investments Permanent 30% Capital Long-term / illiquid 20% Investments 10% 0% (1) MAIN's Investments Investments Capital at Cost at FMV (1) As of March 31, 2017; Investment Assets exclude investments in our Other Portfolio and MSC Adviser I, LLC Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 4

Match Funding with Investment Assets (1) 100% Main Street maintains a 90% capital structure that is designed to match our 80% capital funding with our Floating investment assets 70% Rate • The floating and fixed 60% rate nature of our debt capital sources are 50% opportunistically (% of total) matched with the 40% nature of our debt investments 30% Fixed • Provides opportunity Rate 20% for significant investment income 10% accretion in a rising rate environment, with 0% limited downside MAIN's Debt Investments Debt Capital at Cost RLOC 5-Year Notes 10-Year Notes SBIC Debt (1) As of March 31, 2017 Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 5

At-The-Market (ATM) Equity Program ATM provides permanent capital to match indefinite or long- ATM Equity Program term holding period for LMM investments provides efficient, low cost capital ATM facilitates maintenance of conservative leverage position • Provides permanent capital to match growth of LMM investments on ATM issued equity is accretive to NAV per share an as-needed basis • ATM provides significant benefits vs traditional overnight Provides significant equity offerings economic cost savings compared to traditional • Provides equity capital and liquidity on an as-needed basis, avoiding dilution overnight equity from larger overnight equity offerings offerings • Provides equity capital at significantly lower cost • Avoids negative impact to stock price from larger overnight equity offerings Raised net proceeds of approximately $155 million since inception in 2015 (1) • Average sale price of $34.72, or approximately 60% above average NAV per share over same period (1) • Resulted in economic cost savings of approximately $7.8 million when compared to traditional overnight equity offering (2) (1) Through March 31, 2017 (2) Assumes 6% all-in cost for traditional overnight equity offering Main Street Capital Corporation NYSE: MAIN mainstcapital.com Page 6