3:30 to 4:30 pm: the opening cross, the initial balance and the first hour

The first hour is the course's window. It breaks down into three phases almost nobody separates: convergence, the opening rotation and the initial balance.

3:30 to 3:33 pm: convergence

At 3:30 pm, each Nasdaq stock opens through its own opening cross, an auction that sets a single opening price. The hundred stocks do not open in the same second: the most liquid within a few dozen milliseconds, the others within the minute, some later. The "official" Nasdaq-100 index is only complete once all its components have opened, which takes one to three minutes.

Meanwhile, the NQ converges toward a value it does not yet know. Arbitrageurs buy or sell the future against the stocks as they open. The footprint shows huge deltas in both directions, the heatmap is unreadable, the book rebuilds. None of this is order flow information. The first three minutes are an absolute non-trade, not out of caution, but because the flow seen there has no opinion.