How HeartFlow Stock Reacted to Its Q2 2026 Earnings, Measured Minute by Minute

HeartFlow missed — and rose. Measured from 20:01 UTC, the stock went from $31.01 to $36.34 in fifteen minutes, +17.19%. Prints like this one are why the reaction is worth measuring separately from the result: positioning, not the income statement, set the first move.

This page is the measured anatomy of that print on 13 August 2026: every earnings-related headline that crossed for HeartFlow, in order, each with the price reaction measured from its own instant.

The print, row by row

The move was not instant. One minute after the print the stock had moved +2.48%; by minute fifteen that had grown to +17.19%. Information this clear still took minutes to be fully priced — the gap between those two numbers is the window in which the market was still reading.

Which line actually moved it

Each row above is measured from its own instant — the price immediately before that specific headline crossed — so the rows can be compared directly. The largest single reaction, +17.19%, belongs to the 20:01 UTC line. By the time the 20:03 UTC line arrived, the measured response was +12.87% — the marginal information in each successive headline decays fast, and the decay is measurable.

Did the first read hold?

It did. By the close of the next session, HeartFlow stood at +35.7% against the prior close — the same direction the first fifteen minutes priced. The instant read and the considered read agreed.

A miss that gets marked up usually means the short side was crowded or the market feared worse. The measurement keeps this honest: the direction of the first fifteen minutes is a fact, whatever the narrative later becomes.

How these numbers were measured

We record the price of the instrument immediately before each headline crosses our tape, then again one minute and fifteen minutes later, together with traded volume against that instrument's own normal. Every figure on this page comes from those recordings — the timestamps are the actual instants the lines crossed. Nothing here is an estimate, a close-to-close change, or a model's guess. The method, the gates every page must pass, and how we correct errors are documented in our editorial standards.