Bitcoin options traders lean bullish as call demand surges

Bitcoin options traders are increasingly betting on price gains, as short-dated calls have gained favor over puts. At the one-week, 25-delta level, demand for calls now exceeds demand for puts. A call option pays out if Bitcoin rises, while a put option pays out if it falls. The 25-delta label refers to options priced moderately away from the current spot price. Traders compare the implied volatility of 25-delta calls against puts, with the gap called the risk reversal or skew.

The broader 25-delta skew turned positive on August 20, 2026, marking the first bullish tilt in roughly 12 months. By mid-September 2026, calls made up approximately 61.4% of total Bitcoin options open interest, with puts accounting for 38.6%. Data from Derive put call open interest at around 305,530 BTC. In the 24-hour volume figures around the initial bullish signal, calls led puts.

In late September, a Derivasys snapshot showed the one-week 25-delta risk reversal rising 1.07 vol points to -0.24, moving from favoring downside protection to roughly neutral. Traders have also stacked larger call open interest at the $80,000, $85,000, and $100,000 strikes for December expiries. Bitcoin spot was trading near $78,000 when the skew flipped positive, later consolidating between $80,000 and $85,000.

Futures open interest reached about $52.6 billion around the time of the skew flip. Large open interest at $80,000 and $85,000 could influence short-term price action as expiry approaches. When dealers hedge their exposure, their buying and selling around popular strikes can affect prices. The Derivasys reading of -0.24 indicates near-term skew was neutral rather than bullish, with a crowded market potentially unwinding abruptly if macro conditions sour.