Bitcoin’s options market has undergone a dramatic reversal, shifting from last year’s aggressively bullish positioning to a decidedly bearish setup as the cryptocurrency drops over 25% from its October highs.

Since late last year, traders on Deribit had been heavily concentrated in upside bets, loading up on call options with strike prices of $100,000, $120,000 and even $140,000. For months, the $140,000 call dominated the board, holding more than $2 billion in notional open interest.

That trend has now flipped. Open interest in the previously dominant $140,000 call has fallen to $1.63 billion, while the $85,000 put has surged to the top with $2.05 billion in open contracts. Puts at $80,000 and $90,000 have also overtaken the once-popular $140,000 call, signaling a sharp turn in sentiment as bitcoin trades near $91,000.

Puts, which give traders the right to sell bitcoin at a preset price, are typically used to express or hedge against bearish expectations—while calls express bullish conviction. Recent OI flows show traders increasingly stacking up out-of-the-money puts, preparing for or protecting against deeper declines.

Even though calls still outnumber puts in absolute terms, the pricing tells a different story. Put options are commanding a steep premium relative to calls, reflecting elevated demand for downside protection.

“Options reflect caution heading into year-end,” said Deribit Chief Commercial Officer Jean-David Pequignot. “Short-dated puts between $84K and $80K have seen the strongest volumes today. Front-end implied volatility is around 50%, and the curve shows a pronounced put skew of +5% to +6.5%.”

The bearish tilt is visible across both centralized and decentralized venues. On Derive.xyz, the 30-day skew has fallen to -5.3% from -2.9%, indicating traders are paying increasingly higher premiums for put protection.

Dr. Sean Dawson, head of research at Derive.xyz, said a notable buildup of put open interest is forming around the December 26 expiry—particularly at the $80,000 strike. He noted that macro uncertainty is playing a major role, with weak U.S. labor indicators and fading expectations of a December rate cut leaving traders hesitant to take bullish exposure into year-end.

Despite the sour mood, some indicators suggest the sell-off may be nearing exhaustion. Technical gauges show bitcoin approaching oversold territory, and sentiment has reached extreme pessimism.

“With the Fear & Greed Index near 15 and RSI approaching 30, we’re seeing whale wallets holding more than 1,000 BTC increase meaningfully over the past week,” Pequignot said, pointing to accumulation by large holders.

“Downside concerns are justified in the short term, and the path of least resistance is still lower,” he added. “But extreme setups like this have historically rewarded those willing to take bold positions in crypto.”