Bain Capital GSS Investment Sponsor LLC - 29 Sep 2025 Form 3 Insider Report for Bain Capital GSS Investment Corp. (BCSS)

Role: 10%+ Owner
Signature: /s/ Angelo Rufino, Authorized Signatory of Bain Capital GSS Investment Sponsor LLC
Issuer symbol: BCSS
Transactions as of: 29 Sep 2025
Net transactions value: $0
Form type: 3
Filing time: 01 Oct 2025, 17:30:37 UTC
Next filing: 22 Dec 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Bain Capital GSS Investment Sponsor LLC	10%+ Owner	200 CLARENDON STREET, BOSTON	/s/ Angelo Rufino, Authorized Signatory of Bain Capital GSS Investment Sponsor LLC	01 Oct 2025	0002083643

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
holding	BCSS	Class A ordinary shares, par value $0.0001 per share						900,000	29 Sep 2025	Direct	F3

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
holding	BCSS	Class B ordinary shares, par value $0.0001							29 Sep 2025	Class A ordinary shares, par value $0.0001 per share	12,370,000		Direct	F1, F2, F4, F5

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	This Form 3 is being filed by Bain Capital GGS Investment Sponsor LLC (the "Sponsor") and . The Sponsor is controlled by its controlling members. As a result, each of the Sponsor and its controlling members may be deemed to have beneficial ownership of the Class B ordinary shares and the Private Placement Units (as defined below) (including the Private Placement Shares (as defined below) included in such units) held by our Sponsor.
F2	The reporting person under this Form 3 disclaims beneficial ownership of the Class B ordinary shares reported herein except to the extent of their respective pecuniary interest therein and the filing of this Form 3 shall not be construed as an admission that any such reporting person is the beneficial owner of any Class B ordinary share covered by this Form 3.
F3	Represents Class A ordinary shares, par value $0.0001, of the issuer (the "Private Placement Shares") that are included in the 900,000 private placement units (the "Private Placement Units") that will be purchased by the Sponsor from the issuer in a private placement at $10.00 per Private Placement Unit (the "Private Placement"), as described in the issuer's registration statement on Form S-1 (File No. 333-290126) (the "Registration Statement"). Each Private Placement Unit is comprised of one Private Placement Share and one-fifth of one warrant (the "Private Placement Warrants"), each whole Private Placement Warrant exercisable to purchase one Private Placement Share. Does not represent any Private Placement Shares issuable upon the exercise of Private Placement Warrants.
F4	Pursuant to the Issuer's amended and restated memorandum and articles of association, the Class B ordinary shares have no expiration date and will automatically convert into Class A ordinary shares at the time of the Issuer's initial business combination on a one-for-one basis subject to adjustment pursuant to certain anti-dilution rights.
F5	The Class B ordinary shares reported herein include up to 1,500,000 Class B ordinary shares that are subject to forfeiture to the extent the underwriters of the initial public offering of the issuer's securities do not exercise in full their over-allotment option, as described in the Registration Statement. The over-allotment option of the underwriters expires 45-day from the date of the final prospectus related to the issuer's initial public offering.