BlackRock BUIDL · Reserve-asset Adoption Matrix across stablecoin and DeFi Protocols

Wiki route

This entry sits under fintech index. Read it with Japan financial regulation — legal framework for tokens, crypto-assets, and payments for adjacent context and Japan stablecoin legal framework: three-layer structure (JPYC, USDC, Project Pax) for the broader system boundary.

[!info] TL;DR Since GENIUS Act §501 , BUIDL has been the sole entity that is a neutral reserve asset spanning every “white-circle” + “DeFi gray-circle” SC issuer — USDB (Stripe/Bridge) / Frax sfrxUSD / Ondo OUSG / Ethena USDtb / Spark sUSDS all incorporate BUIDL into their reserves or collateral in some form. BUIDL is at the same time accepted as derivatives margin by CME / Binance / Deribit / Crypto.com. This “indiscriminate servicing” is BlackRock’s positioning as a neutral arms dealer, forming a mirror image of JPMorgan’s closed-loop banking model.

Key facts

• USDB (Stripe/Bridge): operated mainly in BlackRock MMFs · ~$1.8B via BUIDL ^•
• Frax sfrxUSD: in v3 , BUIDL replaced part of the USDC · ~$200M ^•
• Ondo OUSG: the backend is 100% BUIDL · ~$650M ^•
• Ethena USDtb: fully backed by BUIDL · ~$1.4B ^•
• Spark sUSDS (Maker → Sky): held indirectly via an RWA vault · ~$300M ^•
• Those accepting it as IM collateral: CME (prime broker), Binance (BNB Chain 2025-11), Deribit, Crypto.com ^•
• Apollo ACRED uses BUIDL as redemption liquidity ^•

Mechanism / How it works

BUIDL is utilized in 3 roles simultaneously: (1) SC reserve asset — by holding BUIDL an issuer leverages “Treasury yield” through “SC circulation”; (2) DeFi protocol collateral — by taking BUIDL into an RWA vault, decentralized SCs such as USDS / sfrxUSD can also indirectly access institutional-grade compliant reserves; (3) derivatives IM — by exchanges and prime brokers listing BUIDL as eligible margin, institutions can enjoy 4.3% APY without moving cash. Spanning white-circle + gray-circle is the key: BUIDL does not pick its customers (neutral arms dealer); anyone who passes KYC can purchase it → this is a mirror image of JPMorgan JPMD‘s closed-loop model that serves only its own customers, and also echoes the neutral-arms-dealer paradigm of Wall Street crypto-network neutrality.

Origin & evolution

2024-03 At BUIDL’s launch, it mainly served the single customer Ondo OUSG (initially $400M+ via Ondo). 2024-Q4 Ethena USDtb + Frax v3 + Spark RWA vault connected. 2025-Q3 After USDB (Stripe/Bridge) launched, it became the largest single SC-issuer customer. 2025-11 Binance connected BUIDL as IM on BNB Chain — the first case of a CEX directly accepting a tokenized MMF as margin, extending the standard template of CEX RWA collateral integration. 2026-Q1 Apollo ACRED adopted BUIDL as a backup for redemption liquidity — the first case of a private credit fund solving T+0 liquidity with BUIDL. With 2026-05-14’s $1B instant-redemption facility, BUIDL further consolidated its position as a central node of the liquidity network.

Related

• Wiki Index
• BlackRock BUIDL tokenized MMF benchmark
• Reserve-asset interlock flywheel
• Sky USDS
• Frax frxUSD
• stablecoin interest-distribution economics

Sources

• Public disclosures of Apollo ACRED + Ethena USDtb + Ondo OUSG and the onchain attestation of BUIDL