ORBIMED ADVISORS LLC 4

What Happened

• OrbiMed Advisors LLC — reported as a 10% owner — purchased a total of 1,875,000 shares of Q32 Bio Inc. (QTTB) on May 28, 2026. The purchases were two tranches: 1,250,000 shares and 625,000 shares, each at $8.00 per share, for a combined purchase price of $15,000,000. The filing indicates these shares were bought from the issuer in private placements (footnote F1). This is a purchase (potentially viewed as a bullish signal), not a sale.

Key Details

• Transaction date: May 28, 2026
• Price and size: 1,250,000 shares @ $8.00 ($10,000,000) and 625,000 shares @ $8.00 ($5,000,000); total 1,875,000 shares for $15,000,000
• Transaction code: P (Purchase); footnote clarifies private placement from the issuer (F1)
• Record holders and structure: Shares held of record by OrbiMed Private Investments VII, LP ("OPI VII") and OrbiMed Genesis Master Fund, L.P. ("Genesis"); OrbiMed Advisors, OrbiMed Capital GP VII LLC, and OrbiMed Genesis GP LLC are related entities described in footnotes F2–F3
• Joint filing and disclaimers: Report jointly filed by OrbiMed Advisors, OrbiMed GP, and Genesis GP; each disclaims beneficial ownership except to the extent of any pecuniary interest (F4)
• Board designation: OrbiMed designated Diyong Xu, an OrbiMed Advisors employee, as its representative to the issuer’s board (F4)
• Shares owned after transaction: Not specified in the provided filing text
• Timeliness: Reported on June 1, 2026 for May 28 transactions — filed within Form 4 timing rules (not marked late)

Context

• This is institutional purchasing by a reported 10% holder (OrbiMed-affiliated funds), not an individual executive. Institutional placements can reflect investor interest or financing arrangements rather than personal insider sentiment.
• Because the purchase was a private placement from the issuer (not an open-market buy), it may be tied to a financing or strategic investment rather than routine secondary-market buying.