0002095162-25-000001.txt : 20251216 0002095162-25-000001.hdr.sgml : 20251216 20251216090158 ACCESSION NUMBER: 0002095162-25-000001 CONFORMED SUBMISSION TYPE: D PUBLIC DOCUMENT COUNT: 1 ITEM INFORMATION: Rule 506(b) provides a "safer harbor" for a private offering ITEM INFORMATION: Investment Company Act Section 3(c) ITEM INFORMATION: Section 3(c)(1) ITEM INFORMATION: Section 3(c)(7) FILED AS OF DATE: 20251216 DATE AS OF CHANGE: 20251216 EFFECTIVENESS DATE: 20251216 FILER: COMPANY DATA: COMPANY CONFORMED NAME: William Blair MB Investments, L.P. - OC 2025 Series CENTRAL INDEX KEY: 0002095162 ORGANIZATION NAME: EIN: 392515669 STATE OF INCORPORATION: DE FISCAL YEAR END: 1231 FILING VALUES: FORM TYPE: D SEC ACT: 1933 Act SEC FILE NUMBER: 021-566916 FILM NUMBER: 251573510 BUSINESS ADDRESS: STREET 1: WILLIAM BLAIR BUILDING STREET 2: 150 N. RIVERSIDE PLAZA CITY: CHICAGO STATE: IL ZIP: 60606 BUSINESS PHONE: 312-236-1600 MAIL ADDRESS: STREET 1: WILLIAM BLAIR BUILDING STREET 2: 150 N. RIVERSIDE PLAZA CITY: CHICAGO STATE: IL ZIP: 60606 D 1 primary_doc.xml X0708 D LIVE 0002095162 William Blair MB Investments, L.P. - OC 2025 Series WILLIAM BLAIR BUILDING 150 N. RIVERSIDE PLAZA CHICAGO IL ILLINOIS 60606 312-236-1600 DELAWARE None None Limited Partnership true 2025 General Partner William Blair MB Investments GP, L.L.C. William Blair Building 150 N. Riverside Plaza Chicago IL ILLINOIS 60606 Promoter General Partner of the Issuer Kirsten Olsen William Blair Building 150 N. Riverside Plaza Chicago IL ILLINOIS 60606 Director Managing Director, Head of Private Capital Pooled Investment Fund Private Equity Fund false Decline to Disclose 06b 3C 3C.1 3C.7 false true false true false 0 Indefinite 0 Indefinite false 0 0 0 0 The Issuer's General Partner or an affiliate of the Issuer's General Partner may be entitled to receive a fee in accordance with the Issuer's governing documentation, as amended from time to time. false William Blair MB Investments, L.P. - OC 2025 Series /s/ Kirsten Olsen Kirsten Olsen Managing Director of the General Partner of the Issuer 2025-12-16