I’m working on a long-only ML stock-trading strategy and could use some outside perspective. The historical results looked promising, but the more recent results have been much weaker.
How it trades
It uses one-minute price/volume data, usually enters around 11:30 a.m.–12:30 p.m. ET, and closes everything at 3:55 p.m. No leverage or overnight holds.
It generally takes a small number of trades per day. There’s only one entry per stock per session, and each cash allocation gets used once that day.
I’ve tried engineered features, traditional ML, and neural networks. The current version averages predictions from several model fits.
Results (model | SPY)
- 2020–2024 research backtest | +157.4% | +96.4% |
- 2025 OOS validation | +6.8% | +17.7% |
- 2026 YTD simulated paper trading | −0.4% | +13.7% |
For 2020–2024, Sharpe was 0.90, beta to SPY 0.18, and max drawdown 20.2%. It beat SPY in three of five years.
The edge per trade is thin: roughly 0.1–0.15% net, depending on the period. Average winners are around +2.5%, and average losers around −2.25%. The backtest includes modeled transaction costs at twice our base assumptions.
The weakness also started before the OOS period: 2024 returned −10.6% versus SPY’s +24.9%. Averaging predictions made results less dependent on a particular model fit, but didn’t fix the weak periods.
My concern is that it might be picking relatively good stocks while the broader midday-to-close opportunity has deteriorated. An initial attempt to predict when that trading window would be favorable didn’t show useful skill.
What would you investigate first?
- What simple baseline would best separate stock-picking skill from just trading that time window?
- Would you revisit the fixed end-of-day exit, the training target, or the entry timing first?
- How would you test a “don’t trade today” rule without overfitting?
- With an edge this thin, which execution assumptions would you stress-test hardest?
- After extensive experimentation, what would make you stop researching this approach?
I also have a separate multiweek strategy with stronger historical growth but higher market exposure and drawdown. Combining them improves the historical portfolio metrics, but we want to understand whether the intraday strategy holds up on its own.
Would appreciate specific test ideas, useful controls, or a blunt assessment of what we might be missing.
Happy to share more information if needed.