Just as Wall Street traders come to grips with the Federal Reserve’s interest-rate cut, Friday’s US options expiration threatens to whipsaw the market some more.

U.S. stock index futures edged lower on Friday, taking a pause from the previous session's rally that set Wall Street's main indexes on track for weekly gains after the Federal Reserve took a pivotal stance on monetary policy earlier in the week.

"This would be the third time that stocks entered a cycle where annual returns compound at high teens," Fundstrat's Tom Lee said.