Polymarket prices 51% chance of a $75,000 Bitcoin. Skew is mild.

Polymarket bettors, on a cryptocurrency-based prediction market, put the chance of Bitcoin dropping to $75,000 before the end of September at about 51% in a Friday print, against a 70% chance of climbing back to $80,000 within the month. The same market priced an 18% chance of $85,000 and an 11% chance of $70,000 in September.

The Deribit options book, where institutional hedging actually gets priced, is more measured. The 25-delta put skew for the September 25 expiry, the gap between out-of-the-money puts (strikes below the current price) and comparable calls at the same delta, sat about 1.44 percentage points above calls heading into the September 15-16 FOMC (Federal Reserve interest-rate decision), per Deribit data published Sept. 16. That is a put-bias, not a put-panic. Aggregate open interest on the exchange was still 61% calls against 39% puts in mid-September, a call-to-put ratio of 1.56.

Where volatility actually sits Deribit's DVOL, a 30-day implied volatility index, sat around 38.9% for near-term contracts on Sept. 16, a moderate reading by historical standards. Glassnode's term-structure print from Sept. 6 put 1-week at-the-money (ATM) implied volatility at 37.39%, 1-month at 37.69%, 3-month at 38.87% and 6-month at 40.01%, a normal upward slope. Out-of-the-money strikes on Deribit still carry higher implied volatility than at-the-money ones, the volatility smile that signals traders are paying up for tail protection, but the level is not extreme.

What the strike book says Bitcoin traded just below $77,000 on Friday, down more than a third from the record high near $126,000 it set in October 2025, and briefly touched about $75,240 after the US Federal Reserve raised interest rates by a quarter point to 3.75%-4% on Wednesday, the first increase since July 2023, with one more rise signalled before year-end and no cuts until 2027. The most recent Deribit expiry, on Sept. 11, settled at an official delivery price of $77,234, with PerpFinder data at 06:40 UTC placing expiring notional at $2.24 billion, split $1.40 billion of calls against $844 million of puts. The Aug. 28 expiry before that ran $6.44 billion in notional, with 44,639 calls against 37,061 puts, a put/call ratio of 0.83, and its heaviest open interest at the $75,000 and $80,000 strikes. Max pain, the price at which the most options expire worthless, leaving sellers with the smallest payout, was near $70,000.

The tail-risk question The Polymarket contract and the Deribit skew are not pricing the same thing. Polymarket's "below $75,000" market is a binary bet with a fixed payout window; whether it resolves on a touch or on a settle-below basis was not specified in the sources opened for this piece. Deribit strikes are continuous insurance with strike-by-strike cost. The two readings can both be true: 51% on a binary that resolves by month-end, and 1.44 percentage points of downside skew on a listed-options book that sees $77,000 as the price.