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.

The fund would seek to limit losses in exchange for capping potential gains. According to the SEC filing, it “seeks to provide upside exposure to the iShares Bitcoin Trust ETF (IBIT) and/or similar bitcoin exposure up to an approximate limit, while seeking to provide a level of downside protection.” The management fee has not yet been filled in; subsequent amendments to the filing would lay out the fund’s costs and final terms.

PBIT 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 help cover the cost. The strategy would use three overlapping tranches with staggered monthly start dates, allowing one tranche to expire as a new one begins each month. The fund would also hold fixed-income investments to earn interest.

According to the filing, each tranche’s protection would typically begin at about 90% of the reference asset’s value, limiting initial losses to roughly 10% before fees. The cap on gains would be determined by market conditions when each tranche begins. The fund would have broad discretion to change both the protection level and the upside cap, meaning neither would be fixed.

PBIT would be registered under the Investment Company Act of 1940, the law that governs most mutual funds and ETFs, as part of the iShares Trust. Bloomberg Intelligence analyst James Seyffart said it is BlackRock’s third Bitcoin ETF filing. BlackRock, the world’s largest asset manager, currently offers crypto products only for Bitcoin and Ethereum.

Buffered Bitcoin ETFs are not new. Calamos, First Trust and Innovator already offer defined-outcome funds tied to Bitcoin, a structure that grew up in equity markets before issuers adapted it to crypto. However, Seyffart said that when BlackRock enters this area, it “tends to make a big splash.”

In a post on X on October 19, 2026, Seyffart wrote:

BREAKING🚨 @BlackRock just filed for another Bitcoin ETF. This one will be a "buffer" Bitcoin ETF which will means it will offer downside protection but investors will give up some upside to get that protection. Ticker will be $PBIT . pic.twitter.com/302iMwn2fR — James Seyffart (@JSeyff) October 19, 2026

BlackRock’s IBIT leads Bitcoin ETF flows

The filing came as BlackRock’s IBIT, the largest spot Bitcoin ETF with $66.37 billion in net assets, attracted $665.2 million on Monday, according to SoSoValue. It was the only one of the 12 U.S. spot Bitcoin ETFs to record net inflows that day. Daily flow figures have become a widely followed gauge of demand for bitcoin exposure through these funds.

Fidelity’s FBTC recorded $83.6 million in outflows, while Grayscale’s GBTC lost $54.9 million. Across the funds, total net inflows reached $526.6 million on Monday.

The inflow followed two weeks of selling during which U.S. spot Bitcoin ETFs shed about $910 million. The funds recorded outflows of $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 their launch in January 2024, the funds have recorded $57.4 billion in cumulative net inflows and held $105.46 billion in net assets, according to SoSoValue.

Original report: https://decrypt.co/381385/blackrock-files-for-buffer-bitcoin-et-as-ibit-draws-665m-in-a-day