Exhibit 10(b)(4)(f)

SIXTH AMENDMENT & WAIVER TO SECURED LOAN AND SERVICING AGREEMENT

THIS SIXTH
AMENDMENT & WAIVER, dated as of January 24, 2008 (this Amendment), is entered into in connection with that certain Secured Loan and Servicing Agreement, dated as of August 26, 2005 (as amended, supplemented,
restated or replaced from time to time, the Secured Loan and Servicing Agreement), by and among NewStar Short-Term Funding LLC, as the borrower (together with its successors and assigns in such capacity, the
Borrower), NewStar Financial, Inc., as the originator (together with its successors and assigns in such capacity, the Originator) and as the servicer (together with its successors and assigns in such capacity,
the Servicer), MMP-5 Funding, LLC, as the lender (together with its successors and assigns in such capacity, the Lender), NATIXIS Financial Products Inc. (formerly known as IXIS Financial Products Inc.), as the
Administrative Agent (together with its successors and assigns in such capacity, the Administrative Agent), and U.S. Bank National Association, as the trustee (together with its successors and assigns in such capacity, the
Trustee). Capitalized terms used but not defined herein shall have the meanings provided in the Secured Loan and Servicing Agreement.

R E C I T A L S

WHEREAS, the parties hereto entered into that certain Secured Loan and
Servicing Agreement;

WHEREAS, the parties hereto desire to amend the Secured Loan and Servicing Agreement in certain respects as
provided herein;

WHEREAS, pursuant to and in accordance with Section 13.1 of the Secured Loan and Servicing Agreement,
the Administrative Agent and the Lender desire to provide for a one-time waiver of certain provisions of the Secured Loan and Servicing Agreement in certain respects as provided herein;

NOW, THEREFORE, based upon the above Recitals, the mutual premises and agreements contained herein, and other good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, the parties hereto, intending to be legally bound, hereby agree as follows:

SECTION 1. AMENDMENTS.

1. Section 1.1 to the Secured Loan and Servicing Agreement is hereby amended by
amending the definition of Termination Date by deleting the date, November 24, 2007 and replacing it with the date, May 23, 2008.

2. Section 1.1 to the Secured Loan and Servicing Agreement is hereby amended by amending the definition of Eligible Loan by inserting the following new clause (yy) after clause (xx):



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(yy) upon and after January 24, 2008, if such Loan is a ABS Direct Loan or a
Mezzanine Loan, such Loan will not be an Eligible Loan and shall not be added as part of the Collateral.

3. Section 2.1 of the
Agreement is hereby amended by inserting the following new clause (e) after clause (d):

(e) Notwithstanding anything
contained in this Section 2.1 or contained herein, upon and after January 24, 2008, the Borrower shall be prohibited from and shall cease from acquiring ABS Direct Loans and Mezzanine Loans, and ABS Direct Loans and Mezzanine Loans shall
be prohibited from becoming part of the Collateral without the consent of the Administrative Agent.

SECTION 2. WAIVER.

Each party hereto hereby waives the Termination Date arising from the failure to extend the Termination Date prior to
November 24, 2007.

SECTION 3. AGREEMENT IN FULL FORCE AND EFFECT AS AMENDED AND WAIVED.

Except as specifically amended and waived hereby, all provisions of the Secured Loan and Servicing Agreement shall remain in full force and effect. After
this Amendment becomes effective, all references to the Secured Loan and Servicing Agreement, hereof, herein, or words of similar effect referring to the Secured Loan and Servicing Agreement shall be deemed to mean the
Secured Loan and Servicing Agreement as amended hereby. This Amendment shall not constitute a novation of the Secured Loan and Servicing Agreement, but shall constitute an amendment and a one-time waiver thereof. This Amendment shall not be deemed
to expressly or impliedly waive, amend or supplement any provision of the Secured Loan and Servicing Agreement other than as expressly set forth herein.

SECTION 4. REPRESENTATIONS AND WARRANTIES.

Each of the Originator, the Borrower and the
Servicer represents and warrants with respect to itself as of the date of this Amendment as follows:

(a) it is duly incorporated or
organized, validly existing and in good standing under the laws of its jurisdiction of incorporation or organization;

(b) the execution,
delivery and performance by it of this Amendment are within its powers, have been duly authorized, and do not contravene (A) its charter, by-laws, or other organizational documents, or (B) any Applicable Law;



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(c) no consent, license, permit, approval or authorization of, or registration, filing or declaration
with any governmental authority, is required in connection with the execution, delivery, performance, validity or enforceability of this Amendment by or against it;

(d) this Amendment has been duly executed and delivered by it;

(e) this Amendment constitutes its legal,
valid and binding obligation enforceable against it in accordance with its terms, except as enforceability may be limited by applicable bankruptcy, insolvency, reorganization, moratorium or similar laws affecting the enforcement of creditors
rights generally or by general principles of equity;

(f) it is not in default under the Secured Loan and Servicing Agreement; and

(g) there is no Termination Event, Unmatured Termination Event, or Servicer Default.

SECTION 5. CONDITIONS TO EFFECTIVENESS.

The effectiveness of this Amendment is conditioned upon delivery of executed signature pages by all parties hereto to the Administrative Agent.

SECTION 6. MISCELLANEOUS.

(a) This Amendment may be executed in any number of counterparts (including by facsimile), and by the different parties hereto on the same or separate counterparts, each of which shall be deemed to be an original instrument but all of which
together shall constitute one and the same agreement.

(b) The descriptive headings of the various sections of this Amendment are inserted
for convenience of reference only and shall not be deemed to affect the meaning or construction of any of the provisions hereof.

(c) This
Amendment may not be amended or otherwise modified except as provided in the Secured Loan and Servicing Agreement.

(d) The failure or
unenforceability of any provision hereof shall not affect the other provisions of this Amendment.

(e) Whenever the context and
construction so require, all words used in the singular number herein shall be deemed to have been used in the plural, and vice versa, and the masculine gender shall include the feminine and neuter and the neuter shall include the masculine and
feminine.

(f) This Amendment represents the final agreement between the parties only with respect to the subject matter expressly covered
hereby and may not be contradicted by evidence



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of prior, contemporaneous or subsequent oral agreements between the parties. There are no unwritten oral agreements between the parties.

(g) By its signature below, the Administrative Agent acknowledges that this Amendment shall constitute the notice required by Section 2.1(d) of the
Secured Loan and Servicing Agreement. In addition, the Administrative Agent hereby authorizes and directs the Trustee to execute and deliver this Amendment.

(h) THIS AMENDMENT AND THE RIGHTS AND OBLIGATIONS OF THE PARTIES UNDER THIS AMENDMENT SHALL BE GOVERNED BY AND CONSTRUED AND INTERPRETED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.

[Remainder of Page Intentionally Left Blank]



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IN WITNESS WHEREOF, the parties have caused this Amendment to be executed by their respective officers
thereunto duly authorized, as of the date first above written.



|                             |  |                                                    
|---------------------------- |  | ---------------------------------------------------
|THE BORROWER                 |  | NEWSTAR SHORT-TERM FUNDING LLC                     
|                             | 
|                             |  | By: Newstar Financial, Inc., its Designated Manager
|                             | 
|                             |  | By:  /s/  JOHN J. FRISHKOPF                        
|                             |  | Name: John J. Frishkopf                            
|                             |  | Title: Treasurer                                   
|                             | 
|THE ORIGINATOR AND SERVICER: |  | NEWSTAR FINANCIAL, INC.                            
|                             | 
|                             |  | By:  /s/  JOHN J. FRISHKOPF                        
|                             |  | Name: John J. Frishkopf                            
|                             |  | Title: Treasurer                                   
|                             | 
|THE LENDER:                  |  | MMP-5 FUNDING, LLC                                 
|                             | 
|                             |  | By:  /s/  BERNARD J. ANGELO                        
|                             |  | Name: Bernard J. Angelo                            
|                             |  | Title: Vice President                              
|                             | 
|THE ADMINISTRATIVE AGENT:    |  | NATIXIS FINANCIAL PRODUCTS INC.                    
|                             | 
|                             |  | By:  /s/  RALPH J. INGLESE                         
|                             |  | Name: Ralph J. Inglese                             
|                             |  | Title: Managing Director                           
|                             | 
|                             |  | By:  /s/  CHRISTOPHER HAYDEN                       
|                             |  | Name: Christopher Hayden                           
|                             |  | Title: Managing Director                           



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|             |  |                                                                                    
|------------ |  | -----------------------------------------------------------------------------------
|             | 
|THE TRUSTEE: |  | U.S. BANK NATIONAL ASSOCIATION,not in its individual capacity but solely as Trustee
|             | 
|             |  | By:  /s/  RALPH J. CREASIA Name: Ralph J. Creasia Title: Vice President            



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