When does an option actually stop trading, and what happens when expiration arrives? Mark Longo and Dan Passarelli trace how the calendar grew from monthly expirations to weeklies, daily SPX options, and Monday and Wednesday expirations in select stocks and ETFs.

Along the way, they explain why traditional SPX monthly options can stop trading on Thursday yet settle on Friday morning, how cash settlement differs from physical settlement, and why expiration day can catch traders off guard. They also share stories from the trading floor and answer listener questions.