Enclosed for filing on behalf of New Mountain Guardian III BDC, L.L.C. (the “Company” or the “Fund”), pursuant to Rule 17g-1(g) under the Investment Company Act of 1940, as amended (the “1940 Act”) please find the following:

The Fund has paid its allocable portion of the premium for a $3,500,000 bond, maintained jointly with certain of its affiliates, for the policy period May 19, 2023 to May 19, 2024.

If you have any questions, please do not hesitate to contact me at 212-655-0291.

FINANCIAL INSTITUTION BOND Class Code: 2-14057 AXIS BINDER P-001-000324258-04 Page 1 of 7 BINDER 04/28/2023 FROM: Nicole Santos, Senior Underwriter 1211 Avenue of the Americas, 24th Floor New York, NY 10036 Email: Nicole.Santos@axiscapital.com DELIVERED TO: Thomas Meringer Willis Towers Watson Northeast, Inc. [NYC] 200 Liberty Street, 6th Floor, New York, NY 10281 NOTICE: THESE POLICY FORMS AND THE APPLICABLE RATES ARE EXEMPT FROM THE FILING REQUIREMENTS OF THE NEW YORK STATE INSURANCE DEPARTMENT. HOWEVER, SUCH FORMS AND RATES MUST MEET THE MINIMUM STANDARDS OF THE NEW YORK INSURANCE LAW AND REGULATIONS. This binder expires in 30 days, or on the date the policy is issued, whichever is earlier (unless extended in writing by AXIS). COVERAGE IS BOUND PURSUANT TO THE FOLLOWING TERMS AND CONDITIONS: INSURED AND PRINCIPAL ADDRESS NMF SLF I Inc, New Mountain Guardian IV BDC, L.L.C, New Mountain Guardian III BDC 1633 Broadway, 48th floor New York, NY 10019 BROKER OF RECORD Willis Towers Watson Northeast, Inc. [NYC] 200 Liberty Street, 6th Floor New York, NY 10281

FINANCIAL INSTITUTION BOND Class Code: 2-14057 AXIS BINDER P-001-000324258-04 Page 2 of 7 INSURER AXIS Insurance Company (Admitted) 233 South Wacker Drive, Suite 3510 Chicago, IL 60606 (866) 259-5435 A Stock Insurer BOND FORM Financial Institution Bond (Standard Form No. 14) TSB 5062b 1087 BOND NUMBER P-001-000324258-04 Renewal of: P-001-000324258-04 BOND PERIOD Effective Date: 05/19/2023 Expiration Date: 05/19/2024 Both dates at 12:01 a.m. at the Named Insured’s address stated herein. TOTAL BOND PREMIUM $11,000.00 BROKER COMMISSION 15% SURCHARGE / TAX (included in Total Bond Premium) N/A TOTAL BOND LIMITS OF LIABILITY Bond Single Loss Limit $3,500,000 Please note that the Single Loss Limit is applicable to Bond coverages only and is not subject to any other limits. If an amount is inserted below opposite any specified Insuring Agreement or Coverage, such amount shall be the applicable Single Loss Limit for such Insuring Agreement or Coverage. Any amount set forth below shall be part of and not in addition to amounts set forth above. If “Not Covered” is inserted below opposite any specified Insuring Agreement or Coverage, or if no amount is inserted, such Insuring Agreement or Coverage and any other reference thereto in this bond shall be deemed to be deleted therefrom. INSURING AGREEMENT SINGLE LOSS LIMIT OF LIABILITY SINGLE LOSS DEDUCTIBLE Insuring Agreement (A) – Fidelity $3,500,000 $25,000 Insuring Agreement (B) – On Premises $3,500,000 $25,000 Insuring Agreement (C) – In Transit $3,500,000 $25,000 Insuring Agreement (D) – Forgery or Alteration $3,500,000 $25,000

FINANCIAL INSTITUTION BOND Class Code: 2-14057 AXIS BINDER P-001-000324258-04 Page 3 of 7 Insuring Agreement (E) – Securities $3,500,000 $25,000 Insuring Agreement (F) – Counterfeit Currency $3,500,000 $50,000 Coverage on Partners Not Covered OPTIONAL INSURING AGREEMENTS AND COVERAGES SINGLE LOSS LIMIT OF LIABILITY SINGLE LOSS DEDUCTIBLE Audit Expense $10,000 $1,000 Claim Expense $10,000 $1,000 Computer Systems Fraud $3,500,000 $250,000 Customer Funds Transfer Fraud $3,500,000 $25,000 Facsimile Signature $3,500,000 $25,000 Stop Payment Order Liability $100,000 $10,000 Unauthorized Signatures $100,000 $25,000 Uncollectible Items of Deposit $100,000 $10,000 AGGREGATE Social Engineering LIMIT OF LIABILITY Fraud $25,000 $25,000 with Official Authorization $25,000 NOTICES TO INSURER Send Notice of Claims To: AXIS Insurance Claims Department P.O. Box 4470 Alpharetta, GA 30023-4470 Email: USFNOL@axiscapital.com Phone (Toll-Free): (866) 259-5435 Phone: (678) 746- 9000 Fax: (866) 770-5629 Send All Other Notices And Inquiries To: AXIS Insurance 10000 Avalon Blvd. Suite 200 Alpharetta, GA 30009 Email: notices@axiscapital.com Phone (Toll-Free): (866) 259-5435 Phone: (678) 746- 9000 Fax: (678) 746-9444 CLICK HERE FOR REQUESTED APPLICATIONS AND SUPPLEMENTS If any item requested above is not received, reviewed and accepted by AXIS underwriters and acknowledged as such in writing by the above specified date, then this binder and any policy issued will be automatically deemed void ab initio (as if it had never existed) with no effect. The payment of premium or the issuance of any policy shall not serve to waive the above requirements. Please note that a condition precedent to coverage under this binder is that no material change in the exposure or risk occurs and no submission is made to the insurer of a claim or circumstances that might give rise to a claim between the date of this binder and the inception of the policy. Applicant is under the continuing duty to report any such change and to

FINANCIAL INSTITUTION BOND Class Code: 2-14057 AXIS BINDER P-001-000324258-04 Page 4 of 7 notify us of any such claims or circumstances. A public filing with the Securities and Exchange Commission will be deemed to be compliance with this duty to report. The Insurer may take any action appropriate and allowed under state law in response to such information. For additional information about AXIS Financial Institutions products, please visit our website here.

FINANCIAL INSTITUTION BOND Class Code: 2-14057 AXIS BINDER P-001-000324258-04 Page 5 of 7 SCHEDULE OF FORMS & RIDERS Policyholder Notices and Bond Forms Form Number and Edition Date State Fraud Statement AXIS 104 0415 Policyholder Notice - Economic And Trade Sanctions AXIS 906 0316 Financial Institution Bond (Standard Form No. 14) TSB 5062b 1087 Riders Form Number and Edition Date 1 Audit Expense Insuring Agreement Rider AXIS 1012153 0119 2 Claim Expense Insuring Agreement Rider AXIS 1012155 0119 3 Amend Racketeering Exclusion Rider AXIS 1012161 0119 4 Amend Fidelity Insuring to Include Larceny and Embezzlement Agreement Rider AXIS 1012168 0119 5 Amend Valuation Rider AXIS 1012170 0119 6 Amend Counterfeit Currency or Money Insuring Agreement Rider AXIS 1012171 0119 7 Unauthorized Signatures Insuring Agreement Rider AXIS 1012176 0119 8 Protected Information Exclusion Rider AXIS 1012180 0119 9 Notice of Loss by E-Mail Rider AXIS 1012189 0119 10 Change of Ownership or Control Notice Rider AXIS 1012191 0119 11 Customer Funds Transfer Fraud Insuring Agreement with Call Back for Transfers in Excess of the Deductible Rider AXIS 1012198 0119 12 Amend Ownership or Covered Property Condition Rider AXIS 1012199 0119 13 Stop Payment Order Liability Insuring Agreement Rider AXIS 1012200 0119 14 Uncollectible Items of Deposit Insuring Agreement Rider AXIS 1012202 0722 15 Amend Definition of Employee to Include Affiliated Persons Rider AXIS 1012203 0119 16 AUTOMATIC INCREASE IN LIMITS FOR INVESTMENT FUNDS RIDER AXIS 1012210 0721 17 Automatic Coverage For New Investment Funds Rider AXIS 1012211 0721 18 Investment Company No Deductible Rider AXIS 1012214 0119 19 New York Statutory Rider AXIS 1012253 0119 20 Computer Systems Fraud Insuring Agreement Rider AXIS 1012861 0221 21 Social Engineering Fraud Insuring Agreement With Official Authorization Rider AXIS 1012863 0221 22 Amend Exclusion (M) Rider AXIS 1012869 0421 23 Amend Definition of Property Rider (Does Not Include Non-Fungible Tokens) AXIS 1012870 0521 24 Insuring Agreement (G) Rider SR 5907a 1188 25 New York Statutory Rider SR 6180d 0709

FINANCIAL INSTITUTION BOND Class Code: 2-14057 AXIS BINDER P-001-000324258-04 Page 6 of 7 26 Cryptocurrency Exclusion Rider SR 6343 0321

FINANCIAL INSTITUTION BOND Class Code: 2-14057 AXIS BINDER P-001-000324258-04 Page 7 of 7 Nicole Santos 1211 Avenue of the Americas 24th Floor New York, NY 10036 Nicole.Santos@axiscapital.com FINANCIAL INSTITUTION BOND Invoice Binder BROKER: Willis Towers Watson Northeast, Inc. [NYC] Invoice No.: 872959 200 Liberty Street, 6th Floor Invoice Date: New York, NY 10281 Policy Number: P-001-000324258-04 INSURED: NMF SLF I Inc, New Mountain Guardian IV BDC, L.L.C, New Mountain Guardian III BDC Policy Term: 05/19/2023 to 05/19/2024 1633 Broadway, 48th floor Premium Due Date: 06/18/2023 New York, NY 10019 Reminder: For Premium Accounting, please call (816) 471-6118. Premium is due 30 days from the effective date of the policy. Please include our policy number on your remittance advice. Please Remit Premium To: Lockbox Address: AXIS U.S. Insurance Overnight Address: Wells Fargo Bank, N.A. Box 932745 Attn: Lockbox 932745 Atlanta, GA 31193-2745 3585 Atlanta Ave Hapeville, GA 30354 Wire Transfer: Wells Fargo Bank, N.A. Atlanta, GA ABA: 121000248 SWIFT Code: WFBIUS6S Account Name: AXIS U.S. Insurance Account Number: 2000015141499 Reference: Policy number and Insured Name If you have any problems with getting a wire through, please contact Wells Fargo at 800-521-5006 Please send email to bccc@axiscapital.com with wire confirmation and policy reference. Description Gross Premium Commission Net Premium Gross Annual Premium: Commission: 15% $11,000.00 $1,650.00 $9,350.00 Total Due: $9,350.00

The undersigned, Joseph W. Hartswell, Chief Compliance Officer and Corporate Secretary of New Mountain Guardian III BDC, L.L.C., a Delaware limited liability company (the “Company”), does hereby certify that:

IN WITNESS WHEREOF, the undersigned has caused this certificate to be executed this 15th day of May, 2023.

WHEREAS, Section 17(g) of the Investment Company Act of 1940, as amended (the “1940 Act”), and Rule 17g-1(a) thereunder (“Rule 17g-1”), require business development companies (“BDCs”), such as Guardian III, to provide and maintain a bond which shall be issued by a reputable fidelity insurance company, authorized to do business in the place where the bond is issued, to protect the BDC against larceny and embezzlement, covering each officer and employee of the BDC who may singly, or jointly with others, have access to the securities or funds of the BDC, either directly or through authority to draw upon such funds of, or to direct generally, the disposition of such securities, unless the officer or employee has such access solely through his position as an officer or employee of a bank (each, a “covered person”);

WHERAS, Guardian III has determined to maintain a bond jointly with certain of its affiliates to protect Guardian III against larceny and embezzlement, covering each covered person;

WHEREAS, Rule 17g-1 specifies that the bond may be in the form of (i) an individual bond for each covered person, or a schedule or blanket bond covering such persons, (ii) a blanket bond which names Guardian III as the only insured, or (iii) a bond which names Guardian III and one or more other parties as insureds, as permitted by Rule 17g-1;

WHEREAS, Rule 17g-1 requires that a majority of directors who are not “interested persons” of the BDC, as such term is defined under Section 2(a)(19) of the 1940 Act (the “Independent Directors”), approve periodically (but not less than once every 12 months) the reasonableness of the form and amount of the bond, with due consideration to the value of the aggregate assets of Guardian III to which any covered person may have access, the type and terms of the arrangements made for the custody and safekeeping of such assets, and the nature of securities and other investments to be held by Guardian III, and pursuant to factors contained in Rule 17g-1, which are described in the accompanying memorandum attached hereto;

WHEREAS, under Rule 17g-1, Guardian III is required to make certain filings with the SEC and give certain notices to each member of the Board in connection with the bond, and designate an officer who shall make such filings and give such notices; and

WHEREAS, the Board, including all of the Independent Directors, have considered the expected aggregate value of the securities and funds of Guardian III to which Guardian III’s officers and employees may have access (either directly or through authority to draw upon such funds or to direct generally the disposition of such securities), the type and terms of the arrangements made for the custody of such securities and funds, the nature of securities and other investments to be held by Guardian III, the accounting procedures and controls of Guardian III, the nature and method of conducting the operations of Guardian III, the requirements of Section 17(g) of the 1940 Act and Rule 17g-1 thereunder, and all other factors deemed relevant by the Board, including the Independent Directors.

NOW THEREFORE BE IT RESOLVED, that having considered the expected aggregate value of the securities and funds of Guardian III to which Guardian III’s officers and employees may have access (either directly or through authority to draw upon such funds or to direct generally the disposition of such securities), the type and terms of the arrangements made for the custody of such securities and funds, the nature of securities and other investments to be held by Guardian III, the accounting procedures and controls of Guardian III, the nature and method of conducting the operations of Guardian III, the requirements of Section 17(g) of the 1940 Act and Rule 17g-1 thereunder, and all other factors deemed relevant by the Board, including such Independent Directors, the Board, including all of the Independent Directors, determine that the amount of coverage, type, form, and premium, covering the officers and employees of Guardian III and insuring Guardian III against loss from fraudulent or dishonest acts, including larceny and embezzlement, to be issued by Axis Insurance Company in the amount of 3,500,000 (the “Fidelity Bond”) to be fair and reasonable, and be, and hereby are, approved by the Board, including all of the Independent Directors;

FURTHER RESOLVED, that the Authorized Officers be, and each of them hereby is, authorized to make filings with the SEC, in consultation with counsel to Guardian III, and to give notices as may be required, from time to time, pursuant to Rule 17g-1(g) and Rule 17g-1(h) under the 1940 Act;

FURTHER RESOLVED, that the Authorized Officers be, and each of them hereby is, authorized and directed to amend the Fidelity Bond, in consultation with counsel to Guardian III, and to execute such other documents as he or she may deem necessary or appropriate to effect the intent of this resolution;

FURTHER RESOLVED, that each of the Authorized Officers is hereby authorized in the name and on behalf of Guardian III, to make or cause to be made, and to execute and deliver, all such additional agreements, documents, instruments and certifications and to take all such steps, and to make all such payments, fees and remittances, as any one or more of such officers may at any time or times deem necessary or desirable in order to effectuate the purpose and intent of the foregoing resolutions; and

FURTHER RESOLVED, that any and all actions previously taken by Guardian III or any of its directors, officers or other employees in connection with the documents, and actions contemplated by the foregoing resolutions be, and they hereby are, ratified, confirmed, approved and adopted in all respects as and for the acts and deeds of Guardian III.

Sincerely,


/s/ Joseph W. Hartswell
Joseph W. Hartswell
Chief Compliance Officer and Corporate Secretary