BlackRock’s IBIT Bitcoin ETF dominance and the new options era

BlackRock’s iShares Bitcoin Trust (IBIT) holds the largest share of the spot Bitcoin ETF market. The fund reached $50 billion in assets in December and reached the $70 billion mark faster than the record held by the gold ETF, GLD. As of March 11, 2026, IBIT held 777,872 BTC, which was worth $54.4 billion. The fund captured $37 billion in net inflows during 2024. In January 2026, the fund saw $287.4 million in inflows on a single day. This scale puts IBIT far ahead of its peers. Fidelity’s FBTC holds approximately $17 to $18 billion in assets. Grayscale’s GBTC holds $15 billion. In May 2026, total net assets across all 12 Bitcoin ETFs reached over $134 billion. IBIT accounts for roughly 60% of total spot Bitcoin ETF assets. The fund’s dominance was visible in April 2026, when it captured $2.14 billion in monthly inflows. This growth coincided with Bitcoin hitting $80,000 in May 2026.

The derivatives market for IBIT is growing. The SEC approved a rule change to increase IBIT options position and exercise limits from 250,000 to 1,000,000 contracts, a move that provides institutional traders more room to hedge or express larger views around the spot Bitcoin ETF market. IBIT options launched in November 2024 and saw $1.9 billion in notional exposure on the first day. During that debut, traders moved 354,000 contracts, with 289,000 of those being call options. On October 2, 2026, the total option volume reached 108,018 contracts. Call volume for that session was 64,736 contracts. Put volume reached 43,282 contracts. This session produced a put-call volume ratio of 0.67. You already know that the arrival of spot Bitcoin ETFs changed the accessibility of the asset for traditional investors. Will the increase in position limits attract enough new liquidity to change the way institutional traders manage their Bitcoin exposure?

A fee war is happening among Bitcoin ETF issuers. Morgan Stanley launched the Morgan Stanley Bitcoin Trust (MSBT) on April 8, 2026. MSBT charges a 0.14% annual fee. This is lower than the 0.25% fee charged by IBIT and FBTC.

IBIT is the choice for traders seeking liquidity. The fund is the leader in trading activity, with 63 million shares traded on March 10, 2026. However, Grayscale’s GBTC experienced $17.5 billion in cumulative net outflows after its conversion in January 2024. IBIT remains a primary destination for capital, as it captured $307 million in inflows on March 4, 2026. The fund’s expense ratio stays at 0.25% following the expiration of early promotional waivers.

The concentration of Bitcoin in custody creates a specific market structure. Coinbase Custody holds Bitcoin for nine of the twelve US spot Bitcoin ETFs. As of April 2026, this meant $74 billion, or 80.8% of all ETF-held BTC, sat with Coinbase. IBIT uses Coinbase as its primary custodian. The total amount of Bitcoin held by US spot ETFs is 1.29 million BTC. This is 6.77% of the total mined supply of 19 million coins. If all 1,000,000 IBIT options contracts were exercised, the risk would be 7.474% of the outstanding IBIT shares. This would be 0.278% of all Bitcoin outstanding. About 65% of Bitcoin trading volume now occurs on regulated exchanges.