Wharton School Professor Jeremy Siegel no longer thinks it's vital for the Federal Reserve to implement an emergency interest rate reduction, but still wants policymakers to cut quickly and aggressively.

Siegel caused a stir Monday when he told CNBC that Fed Chair Jerome Powell and his colleagues should institute an emergency 0.75 percentage point decrease now and follow it up with another one in September.

Those comments came with markets cratering amid fears over a recession and concern that the Fed is being too slow-footed in easing policy now that the inflation rate has decelerated. However, positive data since then and a ferocious market rally Thursday apparently have eased the urgency.

"I no longer certainly think it's necessary. But I want [Powell] to move down to 4% as fast as possible," Siegel said during a phone interview. "Would it be bad? No. But would it be necessary? No, not at this time."

The Fed on July 31 voted to hold its key interest rate between 5.25%-5.5%, a decision that quickly came under criticism when a report the next day on weekly jobless claims showed a spike and a manufacturing gauge put the sector further into contraction.

However, data Thursday showed claims moved lower from the previous week, and a service sector reading earlier in the week also was better than expected.

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