The economic stimulus plan agreed on Thursday could unleash a wave of mortgage refinancing that would amplify the effect of the Federal Reserve’s 75 basis-point interest rate cut this week, according to analysts.

While the Fed has cut rates aggressively, until now a large number of home­owners and would-be buyers have not been able to take advantage of the lower interest rates, because of high spreads in the dysfunctional secondary market for jumbo (large denomination) loans.