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Finaxion Research · The Turtles: 55-day breakout · single stocks · Recomputed 2026-09-10

Does the Turtles: 55-day breakout work on LDOS?

The Turtles: 55-day breakout does not beat buy-and-hold on LDOS: -7.4 points a year over 20 years.

Total return
56.7%
Buy and hold
530.2%
CAGR
2.3%
Sharpe
-0.03
Max drawdown
-41.6%
Trades
83
Out of sample
overfit
Years
20
1×4.6×8.5×2007200920112013201520172019202120232025
StrategyLDOS

Findings

  1. The Turtles: 55-day breakout does not beat buy-and-hold on LDOS: -7.4 points a year over 20 years.
  2. Against the S&P 500 over the same window: -8.8 points a year.
  3. Total return +56.7% versus +530.2% for buy-and-hold, with 83 trades.
  4. The result does not hold out of sample: it is overfit.
  5. Maximum drawdown -41.6%.
  6. It beats in neither half of the history (split at 2016).
  7. It ranks #141 of 235 markets for this strategy by annual excess over the S&P 500.

Findings derived from the full panel. Each carries its number and its denominator; the computations are reproducible with artifact 0712690e8935.

Exactly what was tested

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.

How to read it

The verdict compares the strategy with buying and holding LDOS 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)

Every strategy on LDOS → · Full page for The Turtles: 55-day breakout →

How to cite

Finaxion Research (2026). Does the Turtles: 55-day breakout work on LDOS?. Daily backtest 1962-01-01–2026-08-31, artifact 0712690e8935. https://finaxion.app/en/research/donchian-55-breakout/ldos

Not a recommendation. Past performance does not guarantee future results.