Exhibit 10.19





EXECUTION VERSION





AMENDMENT NO. 6 TOSENIOR SECURED REVOLVING CREDIT AGREEMENT



This AMENDMENT NO. 6
TO SENIOR SECURED REVOLVING CREDIT AGREEMENT (this “Amendment), dated as of March 9, 2018, is made with respect to
the Senior Secured Revolving Credit Agreement, dated as of May 8, 2014 (as amended, restated, supplemented or otherwise modified
from time to time, the “Credit Agreement”), among ALCENTRA CAPITAL CORPORATION, a Maryland corporation (the
“Borrower”), the several banks and other financial institutions or entities from time to time party to the Credit
Agreement as lenders (the “Lenders”), and ING CAPITAL LLC, as administrative agent for the Lenders under the
Credit Agreement (in such capacity, together with its successors in such capacity, the “Administrative Agent”).
Capitalized terms not otherwise defined herein shall have the meanings ascribed to them in the Credit Agreement (as amended hereby).



WITNESSETH:



WHEREAS, pursuant to
the Credit Agreement, the Lenders have made certain loans and other extensions of credit to the Borrower; and



WHEREAS, the Borrower
has requested that the Lenders and the Administrative Agent amend certain provisions of the Credit Agreement and the Lenders signatory
hereto and the Administrative Agent have agreed to do so on the terms and subject to the conditions contained in this Amendment.



NOW THEREFORE, in consideration
of the promises and the mutual agreements contained herein, and for other good and valuable consideration, the receipt and sufficiency
of which are hereby acknowledged, the parties hereto hereby agree as follows:



SECTION I AMENDMENTS TO
CREDIT AGREEMENT



Effective as of December
31, 2017, and subject to the terms and conditions set forth below (including the occurrence of the Amendment No. 6 Closing Date),
the Credit Agreement is hereby amended as follows:



(a)Section 6.07 of the Credit Agreement is hereby amended by deleting clause (a) in its entirety and replacing it with the
following (solely for the sake of convenience in reviewing this Amendment, the language changed in this clause (a) of Section 6.07
of the Credit Agreement is set forth in bold italics):



“(a)	Minimum
Stockholders’ Equity. After the Initial Funding Date, (x) the Borrower will not permit Stockholders’
Equity as of the last day of any fiscal quarter of the Borrower (other than any such fiscal quarter ending on December 31,
2017, March 31, 2018 or June 30, 2018) to be less than the greater of (i) 55% of the total assets of the Borrower
and its Subsidiaries as at the last day of such fiscal quarter (determined on a consolidated basis, without duplication, in accordance
with GAAP) and (ii) the sum of (x) 75% of the Borrower’s Stockholders’ Equity as of the Initial Funding Date
after giving effect to the consummation of the IPO, plus (y) 65% of the aggregate net proceeds of all sales of Equity
Interests by the Borrower and its Subsidiaries after the Initial Funding Date (other than the proceeds of sales of Equity Interests
by and among the Borrower and its Subsidiaries), and (y) the Borrower will not permit Stockholders’ Equity as of the
last day of any fiscal quarter of the Borrower ending on December 31, 2017, March 31, 2018 or June 30, 2018 to be less than the
greater of (i) 45% of the total assets of the Borrower and its Subsidiaries as at the last day of such fiscal quarter (determined
on a consolidated basis, without duplication, in accordance with GAAP) and (ii) the sum of (x) $126,201,991 plus (y) 65%
of the aggregate net proceeds of all sales of Equity Interests by the Borrower and its Subsidiaries after December 31, 2017 (other
than the proceeds of sales of Equity Interests by and among the Borrower and its Subsidiaries).”












(b)Section 6.07 of the Credit Agreement is hereby amended by deleting clause (b) in its entirety and replacing it with the
following (solely for the sake of convenience in reviewing this Amendment, the language changed in this clause (b) of Section 6.07
of the Credit Agreement is set forth in bold italics):



“(b) Asset
Coverage Ratio. After the Initial Funding Date, the Borrower will not permit the Asset Coverage Ratio to be less than (x)
from December 31, 2017 through June 30, 2018, 2.00 to 1, and (y) at any other time, 2.25 to 1.”



(c)Section 6.07 of the Credit Agreement is hereby amended by deleting clause (e) in its entirety and replacing it with the
following (solely for the sake of convenience in reviewing this Amendment, the language changed in this clause (e) of Section 6.07
of the Credit Agreement is set forth in bold italics):



“(e)	Obligors’
Net Worth Test. After the Initial Funding Date, the Borrower will not permit the Obligors’ Net Worth, plus the Unsecured
Longer Term Indebtedness Add-Back, to be less than (x) from December 31, 2017 through June 30, 2018, an amount equal to $126,201,991,
and (y) at any other time, an amount equal to $149,559,368.”



SECTION II MISCELLANEOUS



2.1. Conditions to Effectiveness of Amendment. This Amendment shall become effective, with an effective date as of December
31, 2017, on the date (such date, the “Amendment No. 6 Closing Date”) on which the Borrower and the Subsidiary
Guarantors shall have satisfied each of the following conditions precedent (unless a condition shall have been waived in accordance
with Section 9.02 of the Credit Agreement):



(a)Executed Counterparts. The Administrative Agent shall have received from each party hereto either (1) a counterpart
of this Amendment signed on behalf of such party or (2) written evidence satisfactory to the Administrative Agent (which may
include telecopy transmission or electronic mail of a signed signature page to this Amendment) that such party has signed
a counterpart of this Amendment.



(b)Corporate Documents. The Administrative Agent shall have received (x) signature and incumbency certificates of the
officers of such Person executing the Amendment and the other Loan Documents to which it is a party and (y) resolutions of
the board of directors or similar governing body of each Obligor approving and authorizing the execution, delivery and performance
of this Amendment and the other Loan Documents to which it is a party or by which it or its assets may be bound as of the date
hereof, certified as of the date hereof by its secretary or an assistant secretary as being in full force and effect without modification
or amendment.





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(c)Consents. The Borrower shall have obtained and delivered to the Administrative Agent certified copies of all consents,
approvals, authorizations, registrations, or filings (other than any filing required under the Exchange Act or the rules or regulations
promulgated thereunder, including, without limitation, any filing required on Form 8-K) required to be made or obtained by the
Borrower and all guarantors in connection with this Amendment, such consents, approvals, authorizations, registrations, filings
and orders shall be in full force and effect and all applicable waiting periods shall have expired and no investigation or inquiry
by any Governmental Authority regarding the Amendment or any transaction being financed with the proceeds of the Loans shall be
ongoing.



(d)No Litigation. There shall not exist any action, suit, investigation, litigation or proceeding or other legal or
regulatory developments pending or threatened in any court or before any arbitrator or Governmental Authority that relates to the
Amendment or that could have a Material Adverse Effect.



(e)Fees and Expenses. The Borrower shall have paid in full to the Administrative Agent and the Lenders all fees and
expenses related to this Amendment and the Credit Agreement owing as of the date hereof.



(f)Default. No Default or Event of Default shall have occurred and be continuing under the Credit Agreement, this Amendment
or under any Material Indebtedness immediately before and after giving effect to this Amendment.



(g)Other Documents. The Administrative Agent shall have received such other documents as the Administrative Agent may
reasonably request in form and substance satisfactory to the Administrative Agent.



2.2. Representations and Warranties. To induce the other parties hereto to enter into this Amendment, the Borrower represents
and warrants to the Administrative Agent and each of the Lenders that, as of the date hereof and after giving effect to this Amendment:



(a) This Amendment has been duly authorized, executed and delivered by the Borrower and the Subsidiary Guarantor and constitutes
a legal, valid and binding obligation of the Borrower and the Subsidiary Guarantor enforceable in accordance with its terms. The
Credit Agreement, as amended by this Amendment, constitutes the legal, valid and binding obligation of the Borrower enforceable
in accordance with its respective terms.



(b)The representations and warranties set forth in Article III of the Credit Agreement and the representations and warranties
in each other Loan Document are true and correct in all material respects (other than any representation or warranty already qualified
by materiality or Material Adverse Effect, which shall be true and correct in all respects) on and as of the date hereof or as
to any such representations and warranties that refer to a specific date, as of such specific date, with the same effect as though
made on and as of the date hereof.





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2.3. Counterparts. This Amendment may be executed in counterparts (and by different parties hereto on different counterparts),
each of which shall constitute an original, but all of which when taken together shall constitute a single contract. This Amendment
constitutes the entire contract between and among the parties relating to the subject matter hereof and supersedes any and all
previous agreements and understandings, oral or written, relating to the subject matter hereof. Delivery of an executed counterpart
of this Amendment by telecopy or electronic mail shall be effective as delivery of a manually executed counterpart of this Amendment.



2.4. Payment of Expenses. The Borrower agrees to pay and reimburse the Administrative Agent for all of its reasonable
and documented out-of-pocket costs and expenses incurred in connection with this Amendment, including, without limitation, the
reasonable fees, charges and disbursements of legal counsel to the Administrative Agent.



2.5. GOVERNING LAW. THIS AMENDMENT SHALL BE CONSTRUED IN ACCORDANCE WITH AND GOVERNED BY THE LAW OF THE STATE OF NEW YORK.



2.6. WAIVER OF JURY TRIAL. EACH PARTY HERETO HEREBY WAIVES, TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, ANY RIGHT
IT MAY HAVE TO A TRIAL BY JURY IN ANY LEGAL PROCEEDING DIRECTLY OR INDIRECTLY ARISING OUT OF OR RELATING TO THIS AMENDMENT OR THE
TRANSACTIONS CONTEMPLATED HEREBY (WHETHER BASED ON CONTRACT, TORT OR ANY OTHER THEORY). EACH PARTY HERETO (A) CERTIFIES THAT
NO REPRESENTATIVE, AGENT OR ATTORNEY OF ANY OTHER PARTY HAS REPRESENTED, EXPRESSLY OR OTHERWISE, THAT SUCH OTHER PARTY WOULD NOT,
IN THE EVENT OF LITIGATION, SEEK TO ENFORCE THE FOREGOING WAIVER AND (B) ACKNOWLEDGES THAT IT AND THE OTHER PARTIES HERETO
HAVE BEEN INDUCED TO ENTER INTO THIS AMENDMENT BY, AMONG OTHER THINGS, THE MUTUAL WAIVERS AND CERTIFICATIONS IN THIS SECTION.



2.7. Incorporation of Certain Provisions. The provisions of Sections 9.01, 9.07, 9.09 and 9.12 of the Credit Agreement
are hereby incorporated by reference mutatis mutandis as if fully set forth herein.



2.8. Effect of Amendment. Except as expressly set forth herein, this Amendment shall not by implication or otherwise limit,
impair, constitute a waiver of, or otherwise affect the rights and remedies of the Lenders, the Administrative Agent, the Collateral
Agent, the Borrower or the Subsidiary Guarantor under the Credit Agreement or any other Loan Document, and, except as expressly
set forth herein, shall not alter, modify, amend or in any way affect any of the other terms, conditions, obligations, covenants
or agreements contained in the Credit Agreement or any other Loan Document, all of which are ratified and affirmed in all respects
and shall continue in full force and effect. Nothing herein shall be deemed to entitle any Person to a consent to, or a waiver,
amendment, modification or other change of, any of the terms, conditions, obligations, covenants or agreements contained in the
Credit Agreement or any other Loan Document in similar or different circumstances. This Amendment shall apply and be effective
only with respect to the provisions amended herein of the Credit Agreement. Upon the effectiveness of this Amendment, each reference
in the Credit Agreement to “this Agreement,” “hereunder,” “hereof,” “herein” or
words of similar import shall mean and be a reference to the Credit Agreement as amended by this Amendment and each reference in
any other Loan Document shall mean the Credit Agreement as amended hereby. This Amendment shall constitute a Loan Document.





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2.9. Consent and Affirmation. Without limiting the generality of the foregoing, by its execution hereof, each of the Borrower
and the Subsidiary Guarantor hereby, as of the date hereof, (i) consents to this Amendment and the transactions contemplated hereby,
(ii) agrees that the Guarantee and Security Agreement and each of the other Security Documents is in full force and effect, (iii)
confirms its guarantee (solely in the case of the Subsidiary Guarantor) and affirms its obligations under the Guarantee and Security
Agreement and confirms its grant of a security interest in its assets as Collateral for the Secured Obligations (as defined in
the Guarantee and Security Agreement), and (iv) acknowledges and affirms that such guarantee and/or grant is in full force and
effect in respect of, and to secure, the Secured Obligations (as defined in the Guarantee and Security Agreement).



2.10. Release. Each of the Borrower and the Subsidiary Guarantor hereby acknowledges and agrees that: (a) neither it nor
any of its Affiliates has any claim or cause of action against the Administrative Agent, the Collateral Agent or any Lender (or
any of their respective Affiliates, officers, directors, employees, attorneys, consultants or agents) including, but not limited
to, under the Credit Agreement and the other Loan Documents (and each other document entered into in connection therewith), and
(b) the Administrative Agent, the Collateral Agent and each Lender has heretofore properly performed and satisfied in a timely
manner all of its obligations to the Obligors and their Affiliates under the Credit Agreement and the other Loan Documents (and
each other document entered into in connection therewith) that are required to have been performed on or prior to the date hereof.
Accordingly, for and in consideration of the agreements contained in this Amendment and other good and valuable consideration,
each of the Borrower and the Subsidiary Guarantor (for itself and its Affiliates and the successors, assigns, heirs and representatives
of each of the foregoing) (collectively, the “Releasors”) does hereby fully, finally, unconditionally and irrevocably
release and forever discharge the Administrative Agent, the Collateral Agent, each Lender and each of their respective Affiliates,
officers, directors, employees, attorneys, consultants and agents (collectively, the “Released Parties”) from
any and all debts, claims, obligations, damages, costs, attorneys’ fees, suits, demands, liabilities, actions, proceedings
and causes of action, in each case, whether known or unknown, contingent or fixed, direct or indirect, and of whatever nature or
description, and whether in law or in equity, under contract, tort, statute or otherwise, which any Releasor has heretofore had
or now or hereafter can, shall or may have against any Released Party by reason of any act, omission or thing whatsoever done or
omitted to be done on or prior to the date hereof directly arising out of, connected with or related to this Amendment, the Credit
Agreement or any other Loan Document (or any other document entered into in connection therewith), or any act, event or transaction
related or attendant thereto, or the agreements of the Administrative Agent, the Collateral Agent or any Lender contained therein,
or the possession, use, operation or control of any of the assets of any of the Borrower or the Subsidiary Guarantor, or the making
of any Loans or other advances, or the management of such Loans or advances or the Collateral.



[Signature pages follow]





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IN WITNESS WHEREOF, the parties hereto have
caused this Amendment to be duly executed and delivered as of the day and year first above written.





| | ALCENTRA CAPITAL CORPORATION,     
| | ----------------------------------
| | as Borrower                       
| |                                   
| | By:                               
| | Name:                             
| | Title:                            
| |                                   
| | ALCENTRA BDC EQUITY HOLDINGS, LLC,
| | as Subsidiary Guarantor           
| |                                   
| | By:                               
| | Name:                             
| | Title:                            







[Signature Page to Amendment No. 6 to Senior
Secured Revolving Credit Agreement]














| | ING CAPITAL LLC, as Administrative Agent and as a Lender
| | --------------------------------------------------------
| |                                                         
| | By:                                                     
| | Name:                                                   
| | Title:                                                  
| |                                                         
| | By:                                                     
| | Name:                                                   
| | Title:                                                  







[Signature Page to Amendment No. 6 to Senior
Secured Revolving Credit Agreement]












| | STATE STREET BANK AND TRUST COMPANY, as Lender
| | ----------------------------------------------
| |                                               
| | By:                                           
| | Name:                                         
| | Title:                                        







[Signature Page to Amendment No. 6 to Senior
Secured Revolving Credit Agreement]












| | EVERBANK COMMERCIAL FINANCE, INC., as Lender
| | --------------------------------------------
| |                                             
| | By:                                         
| | Name:                                       
| | Title:                                      





[Signature Page to Amendment No. 6 to Senior
Secured Revolving Credit Agreement]












| | STATE BANK AND TRUST COMPANY, SUCCESSOR BY MERGER TO ALOSTAR BANK OF COMMERCE, as Lender
| | ----------------------------------------------------------------------------------------
| |                                                                                         
| | By:                                                                                     
| | Name:                                                                                   
| | Title:                                                                                  







[Signature Page to Amendment No. 6 to Senior
Secured Revolving Credit Agreement]












| | STIFEL BANK & TRUST, as Lender
| | ------------------------------
| |                               
| | By:                           
| | Name:                         
| | Title:                        







[Signature Page to Amendment No. 6 to Senior
Secured Revolving Credit Agreement]














| | RAYMOND JAMES BANK, N.A., as Lender
| | -----------------------------------
| |                                    
| | By:                                
| | Name:                              
| | Title:                             









[Signature Page to Amendment No. 6 to Senior
Secured Revolving Credit Agreement]