BlackRock files for bitcoin ETF with downside protection after 52% BTC drawdown
In brief
- BlackRock filed Monday for the iShares Bitcoin Managed Protect ETF, according to CoinDesk.
- Downside protection level and upside cap are not specified in the filing.
- Calamos says its CBOO fund fell about 1% while bitcoin dropped as much as 52%.
- IBIT, the largest U.S. spot bitcoin ETF, manages more than $65 billion, per CoinDesk.
What BlackRock filed
The proposed fund would build on BlackRock's iShares Bitcoin Trust (IBIT). CoinDesk says IBIT manages more than $65 billion in assets and is the largest of the U.S. spot bitcoin ETFs launched in 2024. The filing lays out the new fund's goal.
"The Fund seeks to provide upside exposure to the iShares Bitcoin Trust ETF and/or similar bitcoin exposure up to an approximate limit, while seeking to provide a level of downside protection," BlackRock said in the filing.
The filing leaves out two key numbers. BlackRock didn't say how much downside protection the fund would offer, or how much of bitcoin's upside investors would give up in return (so both the buffer and the cap are still unknown).
Those two numbers decide how the product works.
Calamos got there first
BlackRock, based in New York City, isn't the first to offer this kind of fund. Calamos launched its first three protected bitcoin ETFs in 2025, giving investors a choice between full downside protection and loss limits of 10% or 20% over a set period. Calamos puts roughly 90% of the funds' assets into U.S. Treasuries and uses the rest to buy bitcoin-linked options. That lets holders benefit when bitcoin rises (up to a set cap) while limiting losses over a defined period.
The selloff put that setup to a real test. Bitcoin tumbled as much as 52% from its record high of roughly $126,000 and was quoted at $82,936.07 when CoinDesk published. A Calamos spokesperson told CoinDesk the Bitcoin Structured Alt Protection ETF – October (CBOO) has dropped just 1% since its one-year protection period began in October 2025. That's the company's own figure, not independently verified performance data.
The money flowing in has been small so far. Matt Kaufman, Calamos' head of ETFs, said in May that the protected funds had drawn between $10 million and $15 million over several weeks while spot bitcoin ETFs saw outflows.
BlackRock's growing bitcoin lineup
BlackRock has already moved beyond plain spot exposure. In June it launched the Bitcoin Premium Income Fund (BITA), which holds bitcoin and IBIT shares and sells call options on roughly 25% to 35% of its portfolio to generate monthly income.
If it launches, the Managed Protect ETF would sit alongside both.
Frequently asked questions
How do protected bitcoin ETFs like Calamos' funds work?
According to CoinDesk, Calamos puts roughly 90% of the funds' assets into U.S. Treasuries and uses the rest to buy bitcoin-linked options. Investors gain when bitcoin rises, up to a set cap, and their losses are limited over a defined period. Calamos offers full downside protection or loss limits of 10% or 20%.
How much downside protection will BlackRock's Managed Protect ETF offer?
BlackRock's filing doesn't say. It also doesn't say how much of bitcoin's upside the fund would capture. The filing only says the fund seeks upside exposure to IBIT up to an approximate limit while providing a level of downside protection.
