BlackRock filed with the SEC on Oct. 19 for the iShares Bitcoin Managed Protection ETF (PBIT), a fund that would hold options and fixed-income securities and gain Bitcoin exposure through derivatives.
The preliminary prospectus excludes direct Bitcoin and spot Bitcoin ETP holdings. The securities cannot be sold until the registration statement becomes effective.
Money that enters PBIT could reach Bitcoin through the dealers on the other side of its options.
The filing registers the proposed fund under the Investment Company Act of 1940, and the prospectus describes three overlapping long call-spread tranches with staggered monthly starts, with one tranche typically replaced each month.
Each tranche would buy calls with a strike near 90% of the reference asset’s value, which gives roughly 10% initial exposure to declines before fees, and sell higher-strike calls that cap gains.
Fixed-income holdings supply income and some loss mitigation. The 80% investment policy counts qualifying fixed-income holdings used to implement the strategy, so it describes an asset mix and leaves Bitcoin exposure per dollar undefined.
Where demand could reach Bitcoin
Dealers who sell PBIT’s options could hedge by trading IBIT shares or Bitcoin futures, or they could net the risk against positions they already hold. The prospectus acknowledges that PBIT’s use of IBIT options could increase IBIT’s assets and fees to BlackRock affiliates.
A dealer that buys existing IBIT shares from another investor leaves IBIT’s Bitcoin holdings unchanged, and new coins arrive when authorized participants create new IBIT shares.
A hypothetical $1 billion PBIT with option notional equal to its assets and a net delta of 0.40 would create $400 million of hedge-equivalent exposure for dealers. If half were hedged through IBIT and a quarter of that demand produced creations, the result is $50 million, about 610 BTC at $82,000.
That arithmetic separates three figures that ETF coverage often merges: fund inflows, directional exposure and spot purchases. A billion dollars entering a protected fund could add a fraction of that to the coins held by spot funds.
Protection is set tranche by tranche
The roughly 10% threshold belongs to individual tranches. Tranches start at different times and carry different strikes, so the portfolio has a separate floor for each tranche.
BlackRock warns that a tranche’s distance to its strike can exceed the original 10% once the reference asset appreciates, and that investors can lose some or all of their investment. With a protection strike at 90 and a reference asset that rallies from 100 to 120, the strike sits 25% below the current level.
Option premiums, caps, fixed income, fees, and other tranches shape the fund’s actual return, so a shareholder’s experience depends on the entry point and timing.
A small category and a large distributor
Calamos launched protected Bitcoin funds in 2025. Its CBOJ held $15.9 million and CBXJ $16.4 million as of Oct. 19.
For the January-series outcome period beginning Feb. 2, 2026, CBOJ had an initial upside cap of 8.36% before fees while targeting full protection. CBXJ, which limits the initial loss to 10% before fees over its outcome period, had a 22.24% cap. PBIT would need about 61 times CBXJ’s current assets to reach $1 billion.
BlackRock reported nearly $15.5 trillion of assets under management at the end of the third quarter. Wealth managers who find unprotected Bitcoin hard to fit in a risk-budgeted portfolio could add PBIT as a new allocation.
Investors could also sell IBIT to buy PBIT, which lowers effective Bitcoin exposure, or add a small position to an existing Bitcoin holding. The first path creates a new category of Bitcoin risk-taker, and the other two reshuffle existing exposure.
Monthly rolls
A dealer holding the opposite side of a long call near its strike may be short gamma and buy into rallies, and a dealer opposite the sold call near the cap may sell into them.
The signs depend on each dealer’s whole book, and offsetting IBIT options, futures, and client positions can cancel the incremental trades. In a hypothetical $1 billion fund with three equal tranches, a replacement spread whose delta is 0.40 higher than the expiring one implies about $133 million of theoretical hedge-equivalent exposure.
Bitcoin trades through weekends while IBIT’s sessions are limited, giving dealers a reason to route some hedging into continuously trading crypto instruments.
Where it goes from here
The filing gives Bitcoin watchers a different set of readings to follow: PBIT’s net assets, IBIT shares outstanding, options notionals and strikes once iShares publishes them, and net creations.