Fee Rate (P90) shows the 90th-percentile fee rate paid by Bitcoin transactions on a given day, in sat/vB. Ninety percent of transactions paid this fee rate or less, so the series captures the high-end layer of block-space competition.
A rising P90 means higher-priority users are bidding more aggressively for inclusion. If P90 rises faster than the median, upper-end competition is tightening before the typical clearing level moves. It is most informative with Median Fee Rate and Fee Rate (P99).
The main limitation is that P90 is still a tail measure. It says little about the center of the market on its own and can make fee pressure look broader than it was. Its value is in isolating the high-end competitive tier.
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