Federal Reserve Governor Christopher Waller said Friday he supported a half percentage point rate cut at this week's meeting because inflation is falling even faster than he had expected.

Citing recent data on consumer and producer prices, Waller told CNBC that the data is showing core inflation, excluding food and energy, in the Fed's preferred measure is running below 1.8% over the past four months. The Fed targets annual inflation at 2%.

"That is what put me back a bit to say, wow, inflation is softening much faster than I thought it was going to, and that is what put me over the edge to say, look, I think 50 [basis points] is the right thing to do," Waller said during an interview with CNBC's Steve Liesman.

Both the consumer and producer price indexes showed increases of 0.2% for the month. On a 12-month basis, the CPI ran at a 2.5% rate.

However, Waller said the more recent data has shown an even stronger trend lower, thus giving the Fed space to ease more as it shifts its focus to supporting the softening labor market.

A week before the Fed meeting, markets were overwhelmingly pricing in a 25 basis point cut. A basis point equals 0.01%.

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