The Thesis
The mean-reversion strategy is one of the oldest ideas in systematic trading: assets that deviate sharply from their recent average tend to snap back. Headmars implements this with a clean, binary RSI rule — buy when RSI drops below 30 (oversold), sell when it climbs above 70 (overbought) — applied to a universe of 24 large-cap U.S. equities spanning tech, financials, healthcare, consumer staples, and energy.
The appeal is intuitive. In a universe of liquid mega-caps like AAPL, MSFT, JPM, and WMT, panic-driven dips and euphoria-driven spikes are common and often temporary. The question is whether that intuition survives rigorous testing.
Backtest Performance
Over 451 days of paper trading, the strategy produced a 14.73% total return with a CAGR of 7.98%. The win rate of 70.6% across 38 trades is the headline number — nearly three in every four trades closed profitably. Max drawdown reached 15.64%, which is meaningful but not alarming for an equity strategy.
The Sharpe ratio of 0.58 tells a more measured story: the returns are real, but the risk-adjusted profile is modest. High turnover (879% annualized) is worth noting — this strategy trades actively, and in a live account, transaction costs and slippage would likely erode the edge more than the flat $1-per-trade fee modeled here.
Walk-Forward Validation: Where the Story Gets Complicated
The strategy did not pass Headmars's validation gate, and the fold-by-fold breakdown explains why.
| Fold | Period | Return | Sharpe | Max DD | Trades |
|---|---|---|---|---|---|
| 1 | Aug 2024 – Jan 2025 | +2.06% | 0.57 | 4.24% | 8 |
| 2 | Jan 2025 – Jul 2025 | +11.10% | 1.32 | 10.53% | 10 |
| 3 | Jul 2025 – Dec 2025 | +2.21% | 0.46 | 8.80% | 6 |
| 4 | Dec 2025 – May 2026 | −2.84% | −0.33 | 14.96% | 10 |
Fold 2 is the outlier that flatters the aggregate numbers — an 11.1% return and a Sharpe of 1.32 in six months is exceptional for a simple RSI rule. Strip that out and the remaining three folds average roughly break-even. The most recent fold (Fold 4) is the out-of-sample period used in validation, and it returned −2.84% with a Sharpe of −0.33. That's the number that failed the gate.
The Probabilistic Sharpe Ratio (PSR) of 0.785 and Deflated Sharpe Ratio (DSR) of 0.304 reinforce the concern. With six trials in the search space, the DSR adjusts for multiple-testing bias — a DSR below 0.5 suggests the observed Sharpe is more likely luck than skill.
Recent Activity: Standing Pat
The last six daily runs (June 23–30) executed zero trades. Cash sits at $7,569 against a portfolio value oscillating between roughly $9,959 and $10,083. The last actual trade was a buy of 21 shares of WMT at $115.75 on May 31.
The quiet spell isn't necessarily a bug — RSI thresholds of 30/70 are strict by design, and a broadly trending or range-bound market can go weeks without triggering either extreme in this universe. But six consecutive no-trade days does mean the strategy is currently contributing nothing while the clock runs on its validation window.
Strengths and Risks
Strengths: Simple, interpretable logic with no curve-fitting risk from complex parameters. High win rate across a diversified large-cap universe. Three of four folds positive.
Risks: Performance is heavily concentrated in one fold. The most recent out-of-sample period was negative. High turnover amplifies live-trading friction. The strategy may underperform in trending markets where oversold keeps getting more oversold.
The mean-reversion agent is on notice: one or two more adverse folds and the validation gap becomes structural, not cyclical.