8-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 OR 15(d)of

The Securities Exchange Act of 1934

Date of Report (Date of earliest event reported) October7, 2020

Main StreetCapital Corporation

(Exact name of registrant as specified in its charter)

Registrant's telephone number, including area code:   713-350-6000

Not Applicable

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ¨

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ¨

On October 7, 2020, the Registrant issued a press release. A copy of such press release is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

The information disclosed under this Item 2.02, including Exhibit 99.1 hereto, is being furnished and shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934 and shall not be deemed incorporated by reference into any filing made under the Securities Act of 1933, except as expressly set forth by specific reference in such filing.

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Exhibit99.1

MainStreet Announces Third Quarter 2020 Private Loan Portfolio Activity

HOUSTON,October 7, 2020 – Main Street Capital Corporation (NYSE: MAIN) (“Main Street”) is pleased to announce the following recent activity in its private loan portfolio. During the third quarter of 2020, Main Street originated approximately $85.0 million in new private loan commitments across five (5) new borrowers and funded net new investments across its private loan portfolio with a cost basis totaling approximately $71.0 million.

The following represent notable new private loan commitments during the third quarter of 2020:

As of September 30, 2020, Main Street’s private loan portfolio included total investments at cost of approximately $823.0 million across 68 unique borrowers. The private loan portfolio, as a percentage of cost, included 90% invested in first lien debt investments, 3% invested in second lien debt investments, and 7% invested in equity investments or other securities.

ABOUTMAIN STREET CAPITAL CORPORATION

Main Street (www.mainstcapital.com) is a principal investment firm that primarily provides long-term debt and equity capital to lower middle market companies and debt capital to middle market companies.  Main Street’s portfolio investments are typically made to support management buyouts, recapitalizations, growth financings, refinancings and acquisitions of companies that operate in diverse industry sectors.  Main Street seeks to partner with entrepreneurs, business owners and management teams and generally provides “one stop” financing alternatives within its lower middle market portfolio.  Main Street’s lower middle market companies generally have annual revenues between $10 million and $150 million.  Main Street’s middle market debt investments are made in businesses that are generally larger in size than its lower middle market portfolio companies.