Thesis
donchian-breakout is a textbook trend-following system: buy the 20-day high, exit on the 20-day low. It runs live over a 24-name large-cap universe spanning tech (AAPL, MSFT, NVDA), financials (JPM, V, MA), healthcare (JNJ, UNH, PFE), staples (KO, PG, WMT), and industrials/energy (CAT, XOM, CVX). The logic is simple and mechanical, which is both its appeal and its constraint — it will never anticipate a move, only confirm one already underway.
Backtest
Over 451 days the strategy returned 6.95% (final equity $10,695.11), a 3.83% CAGR with a Sharpe of 0.34. That headline masks real discomfort: a 21.73% max drawdown and a 38.46% win rate across 108 trades. A sub-40% win rate is normal for breakout systems — they lose small and often, and rely on a few large winners — but pairing it with a 0.34 Sharpe means the winners haven't been carrying enough weight. Turnover of 2,083% is heavy, though at $108 total fees the frictional drag stayed modest here.
Validation
This is where the picture splits. Across four walk-forward folds, three were positive:
- Fold 1 (Aug 2024–Jan 2025): +0.73%, Sharpe 0.21
- Fold 2 (Jan–Jul 2025): −7.46%, Sharpe −1.07 — a chop-driven trend-follower's worst environment
- Fold 3 (Jul–Dec 2025): +14.09%, Sharpe 2.72
- Fold 4 (Dec 2025–May 2026): +11.35%, Sharpe 1.86
The most recent out-of-sample fold looks excellent — 11.35% at a 1.86 Sharpe — and the two latest folds are genuinely strong. But the validation gate still reads FAIL. The reason is in the deflated statistics: a PSR of 0.674 and a DSR of just 0.198 across 6 trials. Once you discount for the number of configurations tried, the evidence that this edge is real — not luck — is thin. The gate is doing its job.
Recent Activity
Live behaviour is the loudest warning. The last executed trades were in early-to-mid June (buys in KO, UNH, ABBV, AAPL; sells in MSFT, CAT). Since then, six consecutive scheduled runs (July 17–24) executed nothing, each rejecting one or two candidate orders. Cash has been frozen at $1,760.89 and total equity has drifted sideways around $10,000. Whatever is blocking those orders — likely position-sizing or cash constraints — the strategy is effectively idle while fully invested, riding existing positions rather than acting on fresh breakouts.
Verdict
The strengths are real: two strong recent folds and a coherent, well-understood thesis. The risks are equally real: a failing deflated-Sharpe gate, a punishing 22% drawdown, a losing fold that shows how badly it handles range-bound markets, and a live book that hasn't traded in over a month. Promising, but not yet trustworthy — keep it in paper until the deflated statistics improve and the order-rejection issue is resolved.