BlackRock Files for Buffer Bitcoin ETF as IBIT Draws $665M in a Day

BlackRock has filed with the Securities and Exchange Commission to launch the iShares Bitcoin Managed Protection ETF, a "buffer" fund that would trade under the ticker PBIT and limit investor losses in exchange for capped gains, according to the Monday filing. The filing landed on the same day that BlackRock's iShares Bitcoin Trust ETF (IBIT) drew $665.2 million — the only net inflow among the 12 U.S. spot Bitcoin ETFs, according to SoSoValue data.

The new fund would not hold Bitcoin or Bitcoin ETFs directly. Instead, it would buy call options on IBIT or similar Bitcoin exposure and sell higher-priced calls to offset the cost, structured in three overlapping tranches with staggered monthly start dates so that one tranche expires and a new one begins each month. It would also hold fixed-income investments to earn interest.

What does the buffer actually protect?

Each tranche's protection typically starts at about 90% of the reference asset's value, capping initial losses at roughly 10% before fees, the filing states. The upside cap is set by market conditions at the start of each tranche, and BlackRock retains broad discretion to adjust both parameters — meaning investors should not expect a fixed outcome.

The fund would register under the Investment Company Act of 1940, the statute governing most U.S. mutual funds and ETFs, as part of the iShares Trust. The management fee line remains blank in the initial filing.

Bloomberg Intelligence analyst James Seyffart noted that this is BlackRock's third Bitcoin ETF filing, and that the asset manager still offers crypto products limited to Bitcoin and Ethereum. Buffered Bitcoin ETFs are not new territory: Calamos, First Trust and Innovator already run defined-outcome funds tied to Bitcoin. But Seyffart said that when BlackRock enters a product category, it "tends to make a big splash."

What does this change for advisers and issuers?

For wealth advisers, PBIT offers a familiar defined-outcome wrapper around Bitcoin exposure — a structure they can place in brokerage accounts without managing options themselves. The monthly tranche laddering smooths the cap-setting risk across the year rather than locking investors into a single annual outcome. The trade-off is structural: in a sustained rally, capped tranches will lag IBIT, and the roughly 10% buffer does not protect against losses beyond that threshold.

For competitors already in the buffer segment, BlackRock's distribution reach and the IBIT options market's depth — the deepest in the spot Bitcoin ETF complex — reset the competitive bar.

Flows context: one fund carried the day

IBIT, the largest spot Bitcoin ETF with $66.37 billion in net assets, absorbed $665.2 million on Monday while Fidelity's FBTC lost $83.6 million and Grayscale's GBTC shed $54.9 million. That left total net inflows of $526.6 million across the 12 funds.

The inflow broke a run of outflows. U.S. spot Bitcoin ETFs shed roughly $910 million over the previous two weeks — $228.6 million last week and $681.1 million the week before — as hotter-than-expected inflation data revived bets on another Federal Reserve rate hike. Through Friday, the funds were down about $615 million for October.

Since the January 2024 launches, the category has accumulated $57.4 billion in cumulative net inflows and now holds $105.46 billion in net assets, according to SoSoValue.

What comes next

The SEC now has the standard review window for the 1940-Act filing, and PBIT cannot list until the commission completes that process. Advisers tracking defined-outcome crypto exposure should watch for the fee disclosure in the amended filing — the one blank field that will determine whether BlackRock undercuts the existing Calamos, First Trust and Innovator buffer funds on cost.