BlackRock filed with the SEC on Oct. 19 to register the iShares Bitcoin Managed Protection ETF (PBIT), a fund designed to gain Bitcoin exposure through derivatives while holding options and fixed-income securities.
The preliminary prospectus does not allow the fund to hold Bitcoin or spot Bitcoin exchange-traded products directly. Its shares cannot be sold until the registration statement becomes effective.
Capital committed to PBIT could reach Bitcoin when dealers take the opposite side of the fund’s options.
The filing registers PBIT under the Investment Company Act of 1940. Its prospectus describes three overlapping long call-spread tranches that begin on staggered monthly schedules, with one tranche typically replaced each month.
Each tranche would purchase call options with a strike price near 90% of the reference asset’s value, providing an initial loss cushion of roughly 10% before fees. Higher-strike calls would be sold to limit potential gains.
Fixed-income holdings would generate income and provide some downside mitigation. Under the fund’s 80% investment policy, qualifying fixed-income positions used to implement the strategy count toward the requirement, leaving Bitcoin exposure per dollar unspecified.
Potential routes to Bitcoin demand
Dealers on the other side of PBIT’s options could hedge with IBIT shares or Bitcoin futures, or offset the risk against positions they already hold. The prospectus notes that PBIT’s use of IBIT options could increase assets in IBIT and generate additional fee income for BlackRock affiliates.
When a dealer buys existing IBIT shares from another investor, the amount of Bitcoin held by the ETF does not change. New coins would enter the fund when authorized participants create additional IBIT shares.
In a hypothetical $1 billion PBIT with option notional equal to its assets and a net delta of 0.40, dealers would have $400 million in hedge-equivalent exposure. If half were hedged through IBIT and one-quarter of that demand resulted in share creations, the implied purchases would total $50 million, or about 610 BTC at $82,000.
The calculation distinguishes three figures often grouped together in ETF coverage: fund inflows, directional exposure and actual spot purchases. A $1 billion inflow into a protected fund could therefore translate into only a fraction of that amount in new Bitcoin bought by spot funds.
Protection is established tranche by tranche
The roughly 10% threshold applies to each individual tranche. Because the tranches begin at different times and use different strikes, the portfolio maintains a separate downside floor for each one.
BlackRock cautions that a tranche’s distance from its strike can exceed the original 10% if the reference asset appreciates. The prospectus also warns that investors could lose some or all of their investment. With a protection strike at 90 and a reference asset rising from 100 to 120, for example, the strike would sit 25% below the current level.
Option premiums, upside caps, fixed-income income, fees and the timing of each tranche would determine the fund’s actual returns, making a shareholder’s outcome dependent on the entry point and holding period.
A specialized strategy with a potential wide distribution
Calamos launched protected Bitcoin funds in 2025. As of Oct. 19, its CBOJ fund held $15.9 million and the CBXJ fund held $16.4 million.
For the January-series outcome period beginning Feb. 2, 2026, CBOJ had an initial upside cap of 8.36% before fees while targeting full downside protection. CBXJ, which limits the initial loss to 10% before fees over its outcome period, had a 22.24% cap. PBIT would need roughly 61 times CBXJ’s current assets to reach $1 billion.
BlackRock reported nearly $15.5 trillion in assets under management at the end of the third quarter. Wealth managers that consider unprotected Bitcoin unsuitable for their portfolio limits could use PBIT as another allocation.
Investors could sell IBIT to buy PBIT, reducing their effective Bitcoin exposure, or add a small PBIT position alongside an existing Bitcoin holding. One route introduces a new type of protected Bitcoin exposure, while the others redistribute exposure investors already hold.
Monthly position rolls
A dealer holding the opposite side of a long call near its strike may be short gamma and need to buy as prices rise. A dealer on the other side of the sold call near the cap may sell into the same advance.
The net effect depends on each dealer’s entire book, and offsetting positions in IBIT options, futures and client holdings could neutralize the additional trades. In a hypothetical $1 billion fund divided into three equal tranches, replacing a spread with one whose delta is 0.40 higher would imply about $133 million in theoretical hedge-equivalent exposure.
Bitcoin trades around the clock, while IBIT operates during limited exchange sessions. That difference gives dealers a reason to route some hedging into continuously traded crypto instruments.
What to watch next
The filing gives market watchers several indicators to monitor: PBIT’s net assets, IBIT shares outstanding, options notionals and strike prices once iShares publishes them, and net share creations.