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BlackRock filed a 17-page comment letter on May 1 asking the Office of the Comptroller of the Currency to eliminate a proposed 20% ceiling on tokenised reserve assets from its draft rules implementing the GENIUS Act. The submission arrived on the final day of the OCC's 60-day public comment window. BlackRock's principal objection is that imposing a fixed quantitative ceiling on tokenised reserves introduces a structural constraint based on ledger infrastructure rather than the credit quality, duration, or liquidity of the underlying assets. The OCC's proposal spans 376 pages and implements the Guiding and Establishing National Innovation for U.S. Stablecoins Act, enacted on July 18, 2025. Under the proposal, eligible stablecoin reserves include U.S. cash, insured bank deposits, certain short-term Treasury notes, government money market funds, and tokenised versions of any of those instruments, to be housed in a new 12 CFR 15.
The cap would directly constrain BUIDL's role as stablecoin reserve infrastructure
The commercial stakes for BlackRock are concrete. Its BUIDL fund — a tokenised money market fund issued by Securitize — holds nearly $2.6 billion in assets and supplies more than 90% of the reserves backing Ethena's USDtb and Jupiter's JupUSD on Solana. A binding 20% cap on tokenised reserves would limit how much of that reserve demand BUIDL could satisfy. Circle's USYC, the current leader in the tokenised Treasury segment at $2.9 billion in AUM, would face the same constraint. BUIDL's institutional footprint has expanded beyond stablecoin reserves: it was accepted as collateral for institutional trading on Binance in November 2025. Beyond opposing the cap, BlackRock made three additional requests: explicit confirmation that Treasury ETFs qualify as eligible reserves under Section 4 of the GENIUS Act, addition of U.S. Treasury floating-rate notes with up to two years of remaining maturity to the eligible reserve list, and adoption of "Option A" — a principles-based reserve diversification framework with optional quantitative safe harbors — rather than "Option B," which would impose mandatory daily quantitative requirements.
The OCC rulemaking is one of five parallel processes with a January 2027 deadline
The 376-page OCC proposal sits alongside parallel rulemakings from the FDIC, Treasury, FinCEN, and OFAC, all facing a January 2027 compliance deadline. BlackRock's submission is one of more than 200 stakeholder responses the OCC is evaluating before finalising the rules. The comment letter does not disclose the specific percentage BlackRock would consider an acceptable alternative ceiling, nor does it propose a revised quantitative threshold. The filing does not identify which stablecoin issuers BlackRock consulted before submitting, and it does not address how BUIDL's reserve-backing role would be restructured if the OCC retains the 20% cap in its final rule. The letter also does not speak to the parallel FDIC, Treasury, FinCEN, or OFAC rulemakings, each of which may impose independent reserve constraints. The immediate effect is that BlackRock's formal opposition is now part of the OCC's administrative record — but it does not establish that the cap will be removed or that the January 2027 deadline will be adjusted.
