BlackRock's spot bitcoin exchange-traded fund, iShares Bitcoin Trust (IBIT), has seen its options open interest (OI) on Nasdaq overtake the size of Deribit's bitcoin options market.

On April 25, blockchain media outlet CoinDesk reported that rapidly growing demand for bitcoin investment and hedging within U.S. regulated markets is also changing the structure of a derivatives market that has been centred offshore.

Based on figures compiled by the decentralised crypto volatility protocol Volmex, IBIT options open interest stood at $27.61 billion on April 25. Deribit's bitcoin options open interest was $26.9 billion the same day. Deribit has operated the bitcoin options market since 2016, but IBIT options, around 2 years old, have surpassed it in size.

Open interest refers to the size of options contracts that have not yet been closed out. It is an indicator of market participation and liquidity. The larger it is, the broader the trading base and the greater the market depth. This reversal shows that regulated bitcoin investment infrastructure in the United States is no longer merely a supporting tool for offshore markets.

The market structure also shows the two products are absorbing different types of demand. Volmex said IBIT call option open interest in the short term was concentrated in an ETF upside-bet zone aimed at scenarios in which bitcoin rises to around $109,709. That is about 41 percent above the current market price of $77,400. Deribit positioning also reflected a bullish view, but the expected price level was $106,000, slightly lower than IBIT.

Volmex analysed that U.S. market call option open interest is clustered in out-of-the-money zones about 4 percentage points farther than the offshore market, and that the average delta is slightly lower. It said this suggests U.S. flows are more influenced by retail-driven upside bets and systematic covered-call strategies.

Expiry preferences also differed. IBIT options, on average, showed a strong preference for October 2026 expiries, while Deribit had a higher share in August expiries. Volmex said IBIT options are skewed toward longer maturities by about 2 months on an open-interest-weighted basis, which it attributed to U.S. ETF investors having a longer investment horizon. It said the result reflects differences in the investor base rather than asymmetries in protection demand or upside expectations.

Sidra Parikh (시드라 파리크), Deribit's head of global retail sales and business, assessed the expansion of IBIT options as a positive trend for the overall market. She said U.S. retail investors cannot easily access platforms like Deribit, so IBIT options provide a channel for direct access to regulated leverage and options exposure. She added that a macro environment of rising supply-chain uncertainty, energy shocks and geopolitical risks is also lifting demand for hedging and options strategies.

Another notable point is that implied volatility for IBIT options is higher than for Deribit-based bitcoin options. Volmex analysed that because ETF holders find it difficult to short bitcoin directly, they buy more put options as a way to guard against downside risk, and that this structural demand keeps IBIT implied volatility somewhat higher.

Options are derivatives in which traders buy and sell the right to buy or sell an underlying asset at a specific price in the future. Investors use them to hedge spot or futures positions, bet on direction and generate additional returns on holdings. At IBIT, a covered-call strategy of holding the ETF while selling call options with strike prices above the current price has become a representative income strategy. Bitcoin holders have so far used similar approaches on Deribit.

The two markets do not play the same role. IBIT options are geared toward demand from investors seeking bitcoin exposure through the U.S. regulatory environment and traditional brokerage channels. Deribit, by contrast, remains a core venue for global investors. Parikh said she does not see it as competition and said that as more participants become familiar with options trading through IBIT, the overall market will expand and exchanges like Deribit can benefit from more sophisticated flows.

This shift in size is less a simple change in numbers than a signal that bitcoin derivatives are taking root in U.S. regulated markets. That makes the next point to watch how price discovery and channels for institutional inflows will be reshaped around which market.