Daytrading SPY: Returns In The First Hour, Middle of The Day and The Last Hour

Being a daytrader is a struggle, so I have lately broken down the trading day into performance during the first hour, the middle of the day and the last hour. Previously I have written two articles about when SPY establishes the high and low during the trading day:

Brett Steenbarger had an interesting post some years back about when during the trading day SPY had the most accumulated returns (I can’t find the post now, he has written hundreds). I remember his conclusion: Most of the return happened in the first and last hour of the trading day, and that the middle had a net loss.

Dividing the trading day into the first hour, the middle/lunch hours and the last hour, we get the following accumulated returns from 2010 until present:
















Most return came in the last hour in this period. But again, the middle of the trading is just noise (at least more noise the in the first and last hour).