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

For all the nail-biting about the economy over the past year, investors had it easy: a 5% yield on short-term U.S. debt, one of the safest investments in the world. Now, the times they are a-changin’—again.

The Federal Reserve's closely followed overnight reverse-repo facility already has begun to reflect Wednesday's big interest-rate cut. Wall Street firms rushed to park extra cash overnight at the facility in the wake of the pandemic,