Small-cap stocks just saw their longest winning streak in three and a half years, after the Federal Reserve recalibrated its monetary policy with a big interest-rate cut.

The decision by the Fed's policy-setting committee to cut interest rates for the first time since March 2020 was prefaced by an unusual amount of market uncertainty as to how much the central bank would lower its benchmark rate from a two-decade high of 5.25% to 5.5%, where it has stood since July 2023.