After options expire on Friday and weekend trading follows immediately, the path of gamma risk looks like this: at the moment of Friday expiry, gamma suddenly drops to zero. But over the two weekend days, market makers reprice using "weekend theta." They push up the implied volatility of options expiring next Monday to make up for the time when they cannot hedge.
Why Friday Expiry Triggers Gamma Behavior Changes
At the exact moment of expiry, gamma for all at-the-money options tends toward infinity. To stay delta neutral, market makers must hedge huge gamma exposure before expiry. This hedging mechanically "pins" the price near a certain level — called a gamma pin.
Data from Greeks.live shows that on July 31, $9.6 billion worth of Bitcoin options expired on Deribit, and the max pain price of $64,000 became the settlement center point. When price has positive gamma above a certain level and negative gamma below it, the order book pins itself at the level where risk exposure flips. That pin is only released at expiry.
After expiry? Short-term gamma concentration is released. Bitget analysis points out that when gamma concentration disappears, Bitcoin moves from a gamma-locked environment to price action driven by fund flows. That does not mean gamma risk is gone — it just shifts from the expired contract to the contract expiring next Monday.
Why Weekends Reprice Gamma Risk
The core weekend change is: trading stops, but information keeps flowing.
Historical data shows that put-selling strategies for Monday-expiring options earn an average of 7.3 basis points, clearly lower than 24.6 basis points on other weekdays, but the Sharpe ratio (0.679) is the highest. This suggests the market systematically overprices weekend gap risk — options bought at Friday's close include a premium to compensate for the weekend when hedging is impossible.
SpotGamma's explanation of weekend theta is straightforward: market makers adjust implied volatility before Friday's close to hedge the extra time decay from two days without trading. This means option implied volatility tends to fall late Friday to block risk-free arbitrage, and by Monday's reopen, that expectation is already reflected in pricing.
Real Case: How Gamma Expiry Affects Weekend Price Action
On July 11, 2026, BTC options with a notional value of $6.8 billion expired, and max pain was $69,500. As the deadline approached, market makers sold spot and then bought it back within 40 minutes, pushing the price around $69,480 and back. That was pure mechanical price action.
Key point: after expiry, market makers recorded a net outflow of 14,200 BTC, of which 9,100 BTC was moved to cold storage. This kind of "inventory clearing" is a typical post-expiry move — market makers adjust positions after expiry to prepare for the next cycle of gamma exposure.
Next Steps
On Friday afternoon UTC time, as the expiry window approaches, watch whether price is "pinned" near max pain — this is not a trend signal, just market maker hedging. Within one or two hours after expiry, suppressed volatility is released and short price wicks can appear. Over the weekend, if price breaks a key level, check whether volume follows; a breakout caused by thin liquidity is less reliable than a signal confirmed after liquidity returns on Monday. In the first two hours of Monday's open, watch how the market digests the weekend move after CME reopens. That is the first confirmation window for the market's true direction.
