Pin Risk at Expiration: Why It Is Worse Than It Sounds (and Where It Disappears)
Pin risk sounds like a minor edge case: the underlying happens to close near your strike. It is worse than it sounds, because the market close and the exercise deadline are not the same moment, and a counterparty you cannot see gets roughly ninety minutes after the bell to decide your fate on prices that move after you have stopped watching. It is also, importantly, a physically-settled problem that cash-settled index options structurally remove.