1 DTE SPX is essentially a coin flip

I’ve been digging through SPX daily data looking for a potential edge, and I found something that challenged one of my assumptions. The common thinking is that after a nasty red day, the market is “due” for a bounce. I wanted to see if the data actually supports that. **Here’s what I found:** **2025** 157 green opens, 105 red opens 35 opened worse than **-0.50%** 42 days opened red and also closed red **20 of those 42 (47.6%)** were followed by a green day **2024** 161 green opens, 98 red opens 22 opened worse than **-0.50%** 44 opened red and closed red **22 of 44 (50.0%)** were followed by a green day **2023** 133 green opens, 128 red opens 35 opened worse than **-0.50%** 48 opened red and closed red **25 of 48 (52.1%)** were followed by a green day **2022 (bear market)** 121 green opens, 141 red opens 71 opened worse than **-0.50%** 71 opened red and closed red **26 of 71 (36.6%)** were followed by a green day **Combined (2022–2025)** **472** lower opens **205** days that opened red and closed red **93** of those 205 days were followed by a green session That’s a **45.4%** next-day bounce rate.