McLaren CEO Zak Brown sent a formal letter to FIA President Mohammed Ben Sulayem calling for immediate rule changes that would permanently prohibit shared ownership structures across multiple Formula 1 teams. The letter escalates warnings Brown issued in 2024, when speculation circulated about consolidation scenarios involving midfield and backmarker squads.

Brown's position is straightforward: no individual, fund, or corporate entity should be permitted to hold material equity stakes in more than one constructor. The push comes as franchise valuations have climbed past $1 billion for established operations, drawing interest from sovereign wealth pools and family offices that view F1 as a sports-media hybrid with global sponsor reach. Brown argues that overlapping ownership creates irresolvable competitive conflicts—pit strategy, driver retention, technical partnerships—that no governance framework can police cleanly. His letter does not name specific transactions or entities, but the timing suggests awareness of exploratory conversations in the paddock that have not yet surfaced publicly.

The McLaren position reflects a broader tension between F1's commercial maturity and its sporting purity. Liberty Media's stewardship has multiplied team values by approximately 3x since 2017, turning equity into tradable assets rather than family legacies or manufacturer PR budgets. That liquidity attracts capital, but capital follows logic that doesn't always align with competitive balance. A private equity firm holding 30% of one team and 25% of another faces unavoidable arbitrage incentives around driver contracts, wind-tunnel hours, and cost-cap interpretations. Brown's argument is that the FIA should close the door before the first such deal prints, not after the third.

The letter also positions McLaren as the grid's loudest voice for structural orthodoxy, a role Brown has leaned into since 2022. He opposed Andretti's entry bid on grounds it diluted prize money without adding commensurate commercial value. He criticized Red Bull's cost-cap breach in 2021 as an enforcement failure. Now he's pre-empting consolidation risk. The stance protects McLaren's competitive position—any multi-team structure likely benefits smaller operations more than top-five incumbents—but it also gives Brown leverage in governance negotiations, where the top teams hold formal veto power on rule changes that affect the sporting code.

The FIA has not publicly responded. Ben Sulayem's presidency has prioritized governance visibility after years of Jean Todt–era inscrutability, but ownership structure sits at the intersection of FIA sporting authority and Formula 1 Management commercial prerogative, a boundary that remains contested. Liberty Media has historically deferred to teams on competitive matters while reserving commercial architecture for itself. Whether a firewall rule falls under sporting integrity or commercial structure will determine whose signature is required.

Watch for formal discussion at the next F1 Commission meeting, likely scheduled for late May. If Brown's letter gains traction, expect counterproposals from teams with smaller balance sheets—Haas, Sauber, Williams—who view partial exit liquidity as essential to long-term survival. Also watch for quiet exploratory calls between FIA legal counsel and team owners over the next 30 days to gauge consensus before any formal vote. The absence of immediate pushback from Red Bull or Mercedes suggests Brown is not alone, which means the rule change may arrive faster than the deals it's designed to block.