The Turtles: 55-day breakout does not beat buy-and-hold on CME: -10.3 points a year over 24 years.
Findings derived from the full panel. Each carries its number and its denominator; the computations are reproducible with artifact 0712690e8935.
Close above the prior 55-day high → entry. Close below the prior 20-day low → exit (original System 2). No pyramiding or ATR sizing: we test the signal alone.
The verdict compares the strategy with buying and holding CME over the same window, with round-trip costs per asset class. “Out of sample” is walk-forward: the rule is fit on one stretch and judged on the next. A result that beats in the full sample but not out of it is overfit. Full methodology in the protocol. How we test.
Open this backtest with its trades Trades (CSV)
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Finaxion Research (2026). Does the Turtles: 55-day breakout work on CME?. Daily backtest 1962-01-01–2026-08-31, artifact 0712690e8935. https://finaxion.app/en/research/donchian-55-breakout/cme
Not a recommendation. Past performance does not guarantee future results.