BlackRock filed on Monday to register a bitcoin-linked exchange-traded fund that aims to limit investor losses while still capturing upside price movement. The move comes after Calamos Investments reported that its own protected bitcoin fund lost only 1% during a period when the broader cryptocurrency market fell more than 50% from its peak.

The filing describes the iShares Bitcoin Managed Protect ETF as a vehicle that would give holders exposure to the iShares Bitcoin Trust and similar bitcoin products, while incorporating a mechanism designed to curb downside risk. BlackRock did not specify the exact level of protection or the cap on gains in the filing.

Calamos, based in Naperville, Illinois, introduced a series of structured products in early 2025 that allocate roughly 90% of assets to U.S. Treasury securities and use the remainder to purchase bitcoin-linked options. Those funds are intended to let investors benefit from price increases up to a predetermined ceiling while restricting losses over a set timeframe. According to a company spokesperson, the October 2025 protection period for one of those funds saw a decline of just 1% despite bitcoin’s 52% drop from its record high near $126,000.

The filing follows BlackRock’s earlier launch of the Bitcoin Premium Income Fund (BITA) in June, which combines bitcoin holdings with shares of its flagship spot bitcoin ETF and sells call options on a portion of the portfolio to generate monthly income. Executives have said the strategy appeals to investors seeking both exposure to digital assets and a source of regular cash flow.

No timeline for regulatory approval or market launch was provided in the filing. The proposal reflects a broader trend among traditional asset managers to develop structured products that address the volatility of cryptocurrency markets while integrating with established financial infrastructure.