Pin Risk
Pin risk is what happens when the underlying sits right at (or very near) the strike of an option as expiry approaches. The option's delta becomes unstable, the hedge requirement flips constantly, and whether the option settles ITM or OTM can come down to the final settlement print.
For writers on Hypercall, pin risk is the main reason expiry day is expensive. It's the single largest source of unexpected P&L swings in the last hours of a position's life.
Why pin risk happens
Far from the strike, an option's delta is stable. Deep ITM calls have delta near 1. Deep OTM calls have delta near 0. Small spot moves don't meaningfully change the hedge.
Near the strike, delta is in flux. For an ATM call, delta is roughly 0.5, but the rate of change (gamma) is high. As spot ticks up and down near the strike, delta swings between 0.4 and 0.6, then between 0.3 and 0.7 as expiry approaches.
At expiry, delta becomes a step function: 0 below the strike, 1 above. The transition is instantaneous.
Drag the Days to Expiry slider on the chart below all the way down. Watch the delta curve get sharper and sharper around the strike, and the gamma peak climb dramatically. That sharpening is pin risk taking shape.
The practical cost for a writer is the constant rebalancing on expiry day. Every rebalance pays spread. Those spreads add up when you're trading 20-30 times in the final hour of a position near its strike.
How Hypercall mitigates pin risk
Hypercall options settle using a 30-minute TWAP of the Hyperliquid oracle price, not a single snapshot. The settlement price is averaged across 07:30 - 08:00 UTC, which dilutes single-tick manipulation or noise at the final moment.
A single-print settlement lets one spike decide the entire payoff. A 30-minute TWAP makes each minute contribute 1/30th of the final number. For a pin, this doesn't eliminate the risk, but it turns a binary outcome into a smoother one: the writer's liability becomes a function of the average price over the window, not the close.
For a writer hedging through the settlement window, this matters: you're not trying to guess the single print at 08:00:00. You're trying to track the TWAP, which is a smoother target.
How portfolio margin handles pin risk
Portfolio margin adds extra margin for options expiring within 48 hours. This is called the short-dated gamma kicker (or gamma_overlay), and it's additive on top of the scenario grid's baseline risk.
The reason: the scenario grid uses discrete spot shocks, and for short-dated options those shocks can under-estimate the real pin-day risk. The gamma kicker is a safety buffer for positions in the pin window. See scenario grid → safety add-ons for the full formula.
Managing pin risk
Related:
- Delta Hedging - The rebalancing process that breaks down near expiry
- Gamma - The Greek that drives pin risk
- Scenario Grid - The gamma kicker that compensates for pin risk in margin
- Settlement - Hypercall's 30-minute TWAP mechanics
- Binary Options - Why pin risk is worse for digitals