Form 4 Filing by Bain Capital GSS Investment Sponsor LLC

This Form 4 filing details a transaction by Bain Capital GSS Investment Sponsor LLC, a ten percent owner of Bain Capital GSS Investment Corp. The transaction, dated December 18, 2025, involved the disposal of 30,000 Class B ordinary shares. These shares, with a par value of $0.0001, are convertible into Class A ordinary shares on a one-for-one basis in the event of the issuer's initial business combination, subject to anti-dilution adjustments. The filing explicitly states that this transaction does not constitute an admission of beneficial ownership beyond the reporting person's pecuniary interest. Following this transaction, the reporting person holds 11,440,000 Class B ordinary shares. The filing is made by Angelo Rufino, Authorized Signatory for Bain Capital GSS Investment Sponsor LLC.