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Exhibit 10.1

FIRST AMENDMENT
TO THIRD AMENDED AND RESTATED CREDIT AGREEMENT

        This FIRST AMENDMENT TO THIRD AMENDED AND RESTATED CREDIT AGREEMENT
(this "Amendment") is effective as of May 28, 2020 (the "Effective Date"), by
and among MAIN STREET CAPITAL CORPORATION, a Maryland corporation (the
"Borrower"), the GUARANTORS party to the Credit Agreement (as defined below)
(the "Guarantors"), TRUIST BANK (the "Administrative Agent") and the lenders
party hereto (the "Lenders").

R E C I T A L S:

        WHEREAS, the Borrower, the Guarantors, the Administrative Agent and the
lenders party thereto have entered into that certain Third Amended and Restated
Credit Agreement dated as of June 5, 2018 (the "Credit Agreement"). Capitalized
terms used in this Amendment that are not otherwise defined in this Amendment
shall have the respective meanings assigned to them in the Credit Agreement.

        WHEREAS, the Borrower and Guarantors have requested that the
Administrative Agent and the Lenders amend the Credit Agreement. The Lenders,
the Administrative Agent, the Borrower and the Guarantors desire to amend the
Credit Agreement upon the terms and conditions hereinafter set forth to modify
Section 5.07 of the Credit Agreement.

        NOW, THEREFORE, in consideration of the Recitals and the mutual promises
contained herein and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the Borrower, the Guarantors, the
Administrative Agent and the Lenders, intending to be legally bound hereby,
agree as follows:

        SECTION 1.    Recitals.    The Recitals are incorporated herein by
reference and shall be deemed to be a part of this Amendment.

        SECTION 2.    Amendment to Section 5.07.    Section 5.07 of the Credit
Agreement is deleted in its entirety and replaced with the following:

SECTION 5.07.    Minimum Consolidated Tangible Net Worth.    Consolidated
Tangible Net Worth shall not be less than the sum of (i) $555,000,000 plus
(ii) 35.0% of the cumulative Net Proceeds of Capital Securities/Conversion of
Debt received after September 27, 2013, calculated quarterly at the end of each
Fiscal Quarter.

        SECTION 3.    Conditions to Effectiveness.    The effectiveness of this
Amendment and the obligations of the Lenders hereunder are subject to the
following conditions:

        (a)   The Borrower shall have delivered to the Administrative Agent the
following in form and substance satisfactory to the Administrative Agent:

          (i)  duly executed counterparts of this Amendment signed by the
Borrower, the Guarantors, the Administrative Agent and the Required Lenders;

         (ii)  a certificate of the Secretary or Assistant Secretary of the
Borrower and each Guarantor, certifying to and attaching the resolutions adopted
by the board of directors (or similar governing body) of such party approving or
consenting to this Amendment and certifying that the Loan Parties'
Organizational Documents and Operating Documents have not changed since the
Closing Date (or, if any Loan Party's Organizational Documents or Operating
Documents have changed since the Closing Date, attaching such Organizational
Documents and Operating Documents);

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        (iii)  a certificate of the Chief Financial Officer or other Responsible
Officer of the Borrower, certifying that (x) as of the date of this Amendment,
all representations and warranties of the Borrower and the Guarantors contained
in this Amendment, the Credit Agreement and the other Loan Documents are true
and correct (except to the extent any such representation or warranty is
expressly stated to have been made as of a specific date, in which case such
representation or warranty is true and correct as of such date), (y) immediately
after giving effect to this Amendment (including any Borrowings in connection
therewith and the application of the proceeds thereof), the Borrower is in
compliance with the covenants contained in Article V of the Credit Agreement,
and (z) no Default or Event of Default has occurred and is continuing, both
immediately before and after giving effect to this Amendment (including any
Borrowings in connection therewith and the application of the proceeds thereof);
and

        (iv)  such other documents or items that the Administrative Agent, the
Lenders or their counsel may reasonably request.

        (b)   As of the date of this Amendment, all representations and
warranties of the Borrower and the Guarantors contained in this Amendment, the
Credit Agreement and the other Loan Documents shall be true and correct (except
to the extent any such representation or warranty is expressly stated to have
been made as of a specific date, in which case such representation or warranty
is true and correct as of such date), (y) immediately after giving effect to
this Amendment (including any Borrowings in connection therewith and the
application of the proceeds thereof), the Borrower shall be in compliance with
the covenants contained in Article V of the Credit Agreement, and (z) no Default
or Event of Default shall have occurred or be continuing, both immediately
before and after giving effect to this Amendment (including any Borrowings in
connection therewith and the application of the proceeds thereof).

        (c)   The Borrower shall have paid to the Administrative Agent, upon
application with appropriate documentation, all reasonable costs and expenses of
the Administrative Agent, including reasonable fees, charges and disbursements
of counsel for the Administrative Agent, incurred in connection with this
Amendment and the transactions contemplated herein.

        SECTION 4.    No Other Amendment.    Except for the amendments set forth
in this Amendment, the text of the Credit Agreement shall remain unchanged and
in full force and effect. On and after the Effective Date, all references to the
Credit Agreement in each of the Loan Documents shall hereafter mean the Credit
Agreement, as amended by this Amendment. This Amendment is not intended to
effect, nor shall it be construed as, a novation. The Credit Agreement and this
Amendment shall be construed together as a single agreement. This Amendment
shall constitute a Loan Document under the terms of the Credit Agreement.
Nothing herein contained shall waive, annul, vary or affect any provision,
condition, covenant or agreement contained in the Credit Agreement, except as
herein amended, nor affect or impair any rights, powers or remedies under the
Credit Agreement as hereby amended. The Lenders and the Administrative Agent do
hereby reserve all of their rights and remedies against all parties who may be
or may hereafter become secondarily liable for the repayment of the Obligations.
The Borrower and Guarantors promise and agree to perform all of the
requirements, conditions, agreements and obligations under the terms of the
Credit Agreement as heretofore and hereby amended, the Credit Agreement, as
amended, and the other Loan Documents being hereby ratified and affirmed. The
Borrower and Guarantors hereby expressly agree that the Credit Agreement, as
amended and the other Loan Documents are in full force and effect.

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        SECTION 5.    Representations and Warranties.    The Borrower and
Guarantors hereby represent and warrant to the Administrative Agent and each of
the Lenders as follows:

        (a)   No Default or Event of Default under the Credit Agreement or any
other Loan Document has occurred and is continuing unwaived by the Lenders on
the date hereof, or shall result from this Amendment.

        (b)   The Borrower and the Guarantors have the power and authority to
enter into this Amendment and to do all such acts and things as are required or
contemplated hereunder or thereunder to be done, observed and performed by them.

        (c)   This Amendment has been duly authorized, validly executed and
delivered by one or more authorized officers of the Borrower and the Guarantors
and constitutes the legal, valid and binding obligations of the Borrower and the
Guarantors enforceable against them in accordance with its terms.

        (d)   The execution and delivery of each of this Amendment and the
performance by the Borrower and the Guarantors hereunder and thereunder do not
and will not require the consent or approval of any regulatory authority or
governmental authority or agency having jurisdiction over the Borrower, or any
Guarantor, nor be in contravention of or in conflict with the articles of
incorporation, bylaws or other organizational documents of the Borrower, or any
Guarantor that is a corporation, the articles of organization or operating
agreement of any Guarantor that is a limited liability company, or the provision
of any statute, or any judgment, order or indenture, instrument, agreement or
undertaking, to which the Borrower, or any Guarantor is party or by which the
assets or properties of the Borrower and the Guarantors are or may become bound.

        SECTION 6.    Counterparts; Governing Law.    This Amendment may be
executed in multiple counterparts, each of which shall be deemed to be an
original and all of which, taken together, shall constitute one and the same
agreement. This Amendment may be delivered by facsimile transmission or by
electronic mail with a .pdf copy or other replicating image attached, and any
printed or copied version of any copy so delivered shall have the same force and
effect as an originally signed counterpart. This Amendment shall be construed in
accordance with and governed by the law of the State of North Carolina.

        SECTION 7.    Amendment.    This Amendment may not be amended or
modified without the written consent of the Required Lenders and the
Administrative Agent.

        SECTION 8.    Further Assurances.    The Loan Parties agree to promptly
take such action, upon the request of the Administrative Agent, as is necessary
to carry out the intent of this Amendment.

        SECTION 9.    Consent by Guarantors.    The Guarantors consent to the
foregoing amendments. The Guarantors promise and agree to perform all of the
requirements, conditions, agreements and obligations under the terms of the
Credit Agreement, as hereby amended, and the other Loan Documents to which they
are party, said Credit Agreement, as hereby amended, and such other Loan
Documents being hereby ratified and affirmed. The Guarantors hereby expressly
agree that the Credit Agreement, as hereby amended, and the other Loan Documents
are in full force and effect.

        SECTION 10.    Severability.    Any provision of this Amendment that is
prohibited or unenforceable in any jurisdiction shall, as to such jurisdiction,
be ineffective only to the extent of such prohibition or unenforceability
without invalidating the remainder of such provision or the remaining provisions
hereof or thereof or affecting the validity or enforceability of such provision
in any other jurisdiction.

        SECTION 11.    Notices.    All notices, requests and other
communications to any party to the Loan Documents, as amended hereby, shall be
given in accordance with the terms of Section 9.01 of the Credit Agreement.

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        IN WITNESS WHEREOF, the parties hereto have executed and delivered, or
have caused their respective duly authorized officers and representatives to
execute and deliver, this Amendment as of the day and year first above written.

    BORROWER:
 
 
MAIN STREET CAPITAL CORPORATION
 
 
By:
 
/s/ BRENT D. SMITH

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(SEAL)         Name:   Brent D. Smith         Title:   Chief Financial Officer
and Treasurer
 
 
GUARANTORS:
 
 
MAIN STREET CAPITAL PARTNERS, LLC
 
 
By:
 
/s/ BRENT D. SMITH

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(SEAL)         Name:   Brent D. Smith         Title:   Chief Financial Officer
and Treasurer
 
 
MAIN STREET EQUITY INTERESTS, INC.
 
 
By:
 
/s/ BRENT D. SMITH

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(SEAL)         Name:   Brent D. Smith         Title:   Chief Financial Officer
and Treasurer
 
 
MS INTERNATIONAL HOLDINGS, INC.
 
 
By:
 
/s/ BRENT D. SMITH

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(SEAL)         Name:   Brent D. Smith         Title:   Chief Financial Officer
and Treasurer
 
 
MAIN STREET CA LENDING, LLC
 
 
By:
 
/s/ BRENT D. SMITH

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(SEAL)         Name:   Brent D. Smith         Title:   Chief Financial Officer
and Treasurer

   

[SIGNATURE PAGE TO FIRST AMENDMENT TO
THIRD AMENDED AND RESTATED CREDIT AGREEMENT]

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    TRUIST BANK,
as Administrative Agent
 
 
By:
 
/s/ DAVID BENNETT

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(SEAL)         Name:   David Bennett         Title:   Director

   

[SIGNATURE PAGE TO FIRST AMENDMENT TO
THIRD AMENDED AND RESTATED CREDIT AGREEMENT]

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    TRUIST BANK,
as a Lender
 
 
By:
 
/s/ DAVID BENNETT

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(SEAL)         Name:   David Bennett         Title:   Director

   

[SIGNATURE PAGE TO FIRST AMENDMENT TO
THIRD AMENDED AND RESTATED CREDIT AGREEMENT]

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    FROST BANK,
as a Lender
 
 
By:
 
/s/ JAKE FITZPATRICK

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(SEAL)         Name:   Jake Fitzpatrick         Title:   Vice President

   

[SIGNATURE PAGE TO FIRST AMENDMENT TO
THIRD AMENDED AND RESTATED CREDIT AGREEMENT]

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    ROYAL BANK OF CANADA,
as a Lender
 
 
By:
 
/s/ GLENN VAN ALLEN

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(SEAL)         Name:   Glenn Van Allen         Title:   Authorized Signatory

   

[SIGNATURE PAGE TO FIRST AMENDMENT TO
THIRD AMENDED AND RESTATED CREDIT AGREEMENT]

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    HANCOCK WHITNEY BANK,
as a Lender
 
 
By:
 
/s/ NATHANIEL ELLIS

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(SEAL)         Name:   Nathaniel Ellis         Title:   Senior Vice President

   

[SIGNATURE PAGE TO FIRST AMENDMENT TO
THIRD AMENDED AND RESTATED CREDIT AGREEMENT]

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    ZIONS BANCORPORATION, N.A. DBA AMEGY BANK,
as a Lender
 
 
By:
 
/s/ MEGAN WIGINTON

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(SEAL)         Name:   Megan Wiginton         Title:   Vice President

   

[SIGNATURE PAGE TO FIRST AMENDMENT TO
THIRD AMENDED AND RESTATED CREDIT AGREEMENT]

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    TEXAS CAPITAL BANK, N.A.,
as a Lender
 
 
By:
 
/s/ EVA PAWELEK

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(SEAL)         Name:   Eva Pawelek         Title:   Senior Vice President

   

[SIGNATURE PAGE TO FIRST AMENDMENT TO
THIRD AMENDED AND RESTATED CREDIT AGREEMENT]

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    CADENCE BANK, N.A.,
as a Lender
 
 
By:
 
/s/ TAYLOR DUCOFF

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(SEAL)         Name:   Taylor Ducoff         Title:   Vice President

   

[SIGNATURE PAGE TO FIRST AMENDMENT TO
THIRD AMENDED AND RESTATED CREDIT AGREEMENT]

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    COMERICA BANK,
as a Lender
 
 
By:
 
/s/ L.J. PERENYI

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(SEAL)         Name:   L.J. Perenyi         Title:   Vice President

   

[SIGNATURE PAGE TO FIRST AMENDMENT TO
THIRD AMENDED AND RESTATED CREDIT AGREEMENT]

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    RAYMOND JAMES BANK, N.A.,
as a Lender
 
 
By:
 
/s/ ALEXANDER L. RODY

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(SEAL)         Name:   Alexander L. Rody         Title:   Senior Vice President

   

[SIGNATURE PAGE TO FIRST AMENDMENT TO
THIRD AMENDED AND RESTATED CREDIT AGREEMENT]

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    BOKF, NA DBA BANK OF TEXAS,
as a Lender
 
 
By:
 
/s/ MARIAN LIVINGSTON

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(SEAL)         Name:   Marian Livingston         Title:   Senior Vice President

   

[SIGNATURE PAGE TO FIRST AMENDMENT TO
THIRD AMENDED AND RESTATED CREDIT AGREEMENT]

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    WOODFOREST NATIONAL BANK,
as a Lender
 
 
By:
 
/s/ ANDY GAINES

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(SEAL)         Name:   Andy Gaines         Title:   Senior Vice President

   

[SIGNATURE PAGE TO FIRST AMENDMENT TO
THIRD AMENDED AND RESTATED CREDIT AGREEMENT]

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    CITY NATIONAL BANK,
as a Lender
 
 
By:
 
/s/ ANDREW MILLER

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(SEAL)         Name:   Andrew Miller         Title:   Vice President

   

[SIGNATURE PAGE TO FIRST AMENDMENT TO
THIRD AMENDED AND RESTATED CREDIT AGREEMENT]

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    FIRST NATIONAL BANK OF PENNSYLVANIA,
as a Lender
 
 
By:
 
/s/ CHARLES W. JONES

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(SEAL)         Name:   Charles W. Jones         Title:   Senior Vice President

   

[SIGNATURE PAGE TO FIRST AMENDMENT TO
THIRD AMENDED AND RESTATED CREDIT AGREEMENT]

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    BANCORPSOUTH BANK,
as a Lender
 
 
By:
 
/s/ PHILLIP M. GONZALEZ

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(SEAL)         Name:   Phillip M. Gonzalez         Title:   Senior Vice
President

   

[SIGNATURE PAGE TO FIRST AMENDMENT TO
THIRD AMENDED AND RESTATED CREDIT AGREEMENT]

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QuickLinks

Exhibit 10.1

FIRST AMENDMENT TO THIRD AMENDED AND RESTATED CREDIT AGREEMENT
R E C I T A L S