McLaren Racing CEO Zak Brown sent a formal letter to FIA President Mohammed Ben Sulayem this week requesting immediate clarification of Formula 1's multi-team ownership regulations, according to people familiar with the correspondence. The letter arrives as at least three current manufacturer partnerships—Red Bull-Ford, Aston Martin-Honda, Alpine-Renault—operate under varying interpretations of Article 4.3 of the FIA sporting regulations, which prohibits single entities from controlling competitive outcomes across multiple entries.

The immediate trigger was Alpine's winter paddock conversations with Haas regarding technical collaboration and possible powertrain supply for 2026, when F1's new engine regulations take effect. Brown's letter specifically names the Alpine-Haas discussions and asks the FIA to define whether a manufacturer supplying engines, gearboxes, and rear suspension to a customer team constitutes "undue influence" under current statutes. The question matters because Alpine's parent company Renault owns 100% of the race team, while Haas operates as a private constructor that has sourced Ferrari powertrains since 2016. A switch to Alpine hardware would create the sport's first full manufacturer-to-privateer supply relationship under the 2026 technical framework, which mandates increased electrical output and synthetic fuel.

Brown's concern extends beyond Alpine. Red Bull Technology currently engineers chassis for both the Red Bull and RB (formerly AlphaTauri) teams, sharing wind tunnel time, simulation platforms, and suspension geometry under a single corporate parent. That arrangement has survived FIA scrutiny since 2006, when Red Bull purchased the Minardi team, because Red Bull Racing and RB technically employ separate design staffs and submit independent homologation documents. But Red Bull's 2026 Ford partnership—a $500 million joint powertrain venture announced in May 2023—introduces new complexity. Ford will not supply engines to any team except Red Bull and RB, giving the Milton Keynes operation exclusive access to a works manufacturer relationship while sister team RB receives identical hardware. Brown's letter asks whether this constitutes preferential treatment that violates the spirit of F1's franchise model, where all ten teams hold ostensibly equal commercial rights under the 2021-2025 Concorde Agreement.

The governance question has commercial weight. McLaren recently announced Global and Aquame sponsorships for 2025, deals worth a combined estimated $18 million annually that assume McLaren competes on a level technical playing field. If the FIA clarifies that multi-team ownership creates permissible competitive advantages—allowing Red Bull to develop parallel cars with shared aero learnings, or Alpine to optimize engine maps specifically for a captive customer—McLaren's sponsor pitch weakens. Family offices and institutional allocators sizing Formula 1 team stakes use revenue multiples between 8x and 12x EBITDA; unclear governance dilutes those valuations. One London-based sports investment fund told colleagues it paused diligence on a minority team stake specifically because the ownership rules lack bright lines.

Brown's letter also touches Aston Martin, which signed a factory Honda partnership for 2026 after Mercedes declined to offer works status beyond 2025. Honda will supply only Aston Martin, giving team owner Lawrence Stroll's operation exclusive Japanese engineering resources while Alpine, Haas, and Williams negotiate powertrain deals from positions of lower leverage. Stroll has invested over $1 billion in Aston Martin Aramco since 2020, including a new Silverstone factory that opened in March 2024. The FIA has not challenged that spending, but Brown's letter argues the governance framework should address whether billionaire owners can create de facto works teams through checkbook partnerships that smaller operators cannot match.

What happens next: The FIA typically responds to team correspondence within 21 days, putting a decision window around mid-January. Watch for whether Ben Sulayem refers the question to the F1 Commission—the ten-team governance body that votes on sporting rule changes—or issues a unilateral technical directive. Alpine's Haas conversations have continued through December; a powertrain supply agreement would likely be announced before the February 15 car launch season begins. McLaren's next board meeting is scheduled for late January, when Zak Brown will brief Bahrain sovereign wealth representatives who hold a minority stake.

The letter lands as F1 team valuations approach $2 billion for top-four constructors, a threshold where institutional buyers demand regulatory certainty. Brown has been clear about wanting stable governance; this is him putting the ask in writing.