BlackRock Files for Protected Bitcoin ETF as Calamos Funds Cushion Selloff

BlackRock filed Monday for the iShares Bitcoin Managed Protect ETF, a fund meant to capture bitcoin’s gains while limiting losses when prices fall. It would build on the iShares Bitcoin Trust, which manages more than $65 billion and is the largest US spot bitcoin ETF. The filing gives no details on how much protection the fund would offer or how much upside investors could capture.

Calamos Fund Avoided Most of Bitcoin’s Drop

Bitcoin fell as much as 52% from its record high of about $126,000, yet Bitcoin Structured Alt Protection ETF for October lost just 1% since its protection period began in October 2025. Calamos launched three protected bitcoin ETFs in early 2025, offering full downside protection or loss limits of 10% or 20% over a set period.

How the Protection Structure Works

Calamos puts roughly 90% of fund assets into US Treasuries and uses the rest to buy bitcoin linked options. Investors benefit from price gains up to a cap while losses are limited over a defined period. Calamos ETF head Matt Kaufman said in May that the funds had drawn between $10 million and $15 million over several weeks, even as spot bitcoin ETFs saw outflows.

In June, BlackRock launched the Bitcoin Premium Income Fund, which holds bitcoin and IBIT shares while selling call options on about 25% to 35% of the portfolio to generate monthly income.