The mood on Wall Street just got better really quickly

Investors may still be nervous about the Delta variant and Afghanistan. But Federal Reserve Chair Jerome Powell eased many worriers on Friday when he signaled that the central bank is not going to hit the panic button anytime soon over inflation concerns.

Wall Street sentiment has improved dramatically in the past few days after Powell hinted that the Fed will take a cautious approach to eventually cutting back — or tapering — its program of bond purchases that have helped keep long-term interest rates low. The CNN Business Fear & Greed Index briefly hit "greed" territory late Monday before sliding back into neutral mode Tuesday morning.