Many, many years ago, I traded with Bache, in those days, there were only monthly options, they stopped trading on Friday; HOWEVER, you could exercise them until 11:30 on Saturday. Good Luck getting that done these days. Plus, in those days, you traded with one Broker, not whomever picked up the phone.
I looked it up:
According to NASDAQ, options technically expire at 11:59 AM Eastern Standard time on the date of expiration, which is a Saturday, oddly enough.
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