Filed Pursuant to Rule 424(b)(3)

Registration No.: 333-265951

AMENDMENT NO. 1 DATED MARCH 4, 2025

(To prospectus supplement dated February 27, 2025

and prospectus dated July 1, 2022)

$250,000,000

BAIN CAPITAL SPECIALTY FINANCE, INC.

Common Stock

This Amendment No. 1 to the Prospectus Supplement amends our prospectus supplement dated February 27, 2025. This amendment should be read in conjunction with the prospectus dated July 1 2022.

Calculation of Filing Fee Tables

Form 424B2

(Form Type)

BAIN CAPITAL SPECIALTY FINANCE, INC.

(Exact Name of Registrant as Specified in its Charter)

Table 1: Newly Registered Securities and Carry Forward Securities

Security Type

Security Class Title

Fee Calculation or Carry forward Rule

Amount Registered

Proposed Maximum Offering Price Per Security

Proposed Maximum Aggregate Offering Price

Fee Rate

Amount of Registration Fee (1)

Carry Forward Form Type

Carry Forward File Number

Carry Forward Initial Effective Date

Filing Fee Previously Paid in Connection with Unsold Securities to be Carried Forward

Fees to Be Paid

Equity

Common Stock, par value $0.001 per share

457(o)(1)

$250,000,000

0.00015310

$38,275.00

Carry Forward Securities

Unallocated (Universal) Shelf

Unallocated (Universal) Shelf

415(a)(6)

Total Offering Amount

$250,000,000

$38,275.00

Total Fees Previously Paid

—

Total Fee Offsets

—

Net Fee Due

$38,275.00

(1) Calculated in accordance with Rule 457(o), based on the proposed maximum aggregate offering price, and Rule 457(r) under the Securities Act of 1933, as amended (the “Securities Act”).

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