BlackRock’s Strategic Income Opportunities (SIO) fund increased its holdings in the iShares Bitcoin Trust (IBIT) by 14% during the quarter from June to September 2025, rising from 2,096,447 shares to 2.39 million and valued at roughly $155.8–$156.0 million as of September 30, 2025. The internal allocation places BlackRock’s own fund among leading institutional accumulators and reframes IBIT as a vehicle for treasury-level deployment rather than only external client exposure.
Institutional accumulation consolidates IBIT’s dominance
The SIO allocation aligned with concentrated institutional buying, reinforcing IBIT’s market lead and highlighting its role in Bitcoin liquidity pathways. Launched in January 2024 with a 0.12% expense ratio, IBIT reported Assets Under Management above $100 billion by November 2025 and accounted for 61.4% of the Bitcoin ETF market, with approximately 649,075 BTC held on behalf of investors.
Other large allocators followed a comparable trajectory. D.E. Shaw lifted exposure 345% to 7.4 million shares, Tudor Investment increased to 3.6 million shares (+82%), and Harvard University nearly tripled holdings to 6.8 million shares valued at $442.8 million. Public-sector participation also emerged: Texas reportedly evaluated Bitcoin as part of a strategic reserve framework, with IBIT positioned as a plausible instrument for implementation. Structural expansion paralleled these flows — Nasdaq ISE has pursued a four-fold increase to IBIT option limits, and BlackRock filed a Premium Income ETF while not advancing a spot Solana product — reflecting ongoing product segmentation. The cumulative investor environment shifted as Bitcoin surpassed $90,000, returning $3.2 billion in ETF gains after a prior drawdown of roughly $6 billion.
Operational consequences follow institutional scale. An internal allocation into a firm-managed ETF heightens governance, custody and disclosure obligations for treasuries, custodians and VASP operators. Segregated custody — the practice of maintaining client assets separately from firm assets — remains essential to mitigate commingling risk and maintain auditability. Beneficial owner refers to the person exercising ultimate control of an asset, and verified beneficial-ownership data is critical to AML supervision and counterparty risk mapping.
Compliance and risk functions face practical workloads: record-retention expansion, provenance tracking, chain-of-custody documentation and enhanced reconciliation for ETF-driven flows. Treasury teams must adapt to concentration risk, execution latency and documentation of approval trails, while custodians prepare for peak-flow stress, liquidity mismatches and onboarding of large-scale institutional orders.
BlackRock’s internal SIO allocation to IBIT signals the ETF’s evolution into a mainstream institutional instrument and raises the operational bar for custody, reporting and governance across the crypto-market infrastructure.
