The Federal Trade Commission told Novo Nordisk and Metsera in a formal letter that the structure of Novo’s proposed buyout — an upfront payment for half the company followed by later consideration — could evade mandatory Hart‑Scott‑Rodino premerger review and risk violating U.S. merger law. The FTC raised concerns that transferring substantial rights to Novo prior to HSR review and imposing operational constraints on Metsera while the deal is pending could create anticompetitive harms before regulators can act. The communication cited by Bloomberg and FTC staffers signals heightened antitrust scrutiny amid an active bidding war with Pfizer and underscores regulatory risks for acquirers who front‑load deal economics or restrict target operations during pending transactions. The FTC did not take a final position on the deal’s legality but requested clarification of the deal mechanics and potential remedies to preserve competitive process. Companies involved: Novo Nordisk (bidder), Metsera (target), Pfizer (competing bidder), and the FTC (regulator). Why it matters: the letter could delay or reshape a major consolidation in the obesity‑drug market and sets a precedent for how the agency will treat creative deal structures that shift control before formal review.