Before CPI was released, the market had already written its answer.
But after the release, there was another answer.

CME FedWatch, December 9 FOMC.
Probability of a rate hike: 100%.
Probability of no change: 0%.

Then that 0% started to move.
A “big step” of 50 basis points: 13.6%.

An inflation rate of 0.4%
not only confirmed a rate hike,
but also got people asking again how big it would be.

29 days until the December FOMC.
The market knows “there will be a hike,”
but not yet “by how much.”