Disney (DIS): three strategies, 2019–2024.

Holding Disney over these years returned 5%, a Sharpe ratio of 0.02. At their default settings one of the three rules beat that Sharpe. Tuned on the first 70% of the period and scored on the rest, none of the three held up.

Against holding it

Each rule at the workspace's default parameters, with 10 basis points of cost on every change of position, over 1,510 trading days.

Total returnSharpeWorst fall
Buy and hold5%0.02−61%
Momentum−27%−0.19−64%
MACD35%0.16−51%
Bollinger−15%−0.24−32%

On years it never saw

For each rule, every combination in its grid was run on the period up to 2023-03-15, the best was picked, and only that one was scored on what came after. How walk-forward works.

PickedSharpe, tunedSharpe, afterVerdict
Momentumlookback 10 · MA 500.46−0.45failed
MACD12 / 26 / 90.57−0.91failed
Bollinger30 days · 2σ0.27−0.86failed

Skill or luck

Three more readings of the same runs. A permutation p-value under 0.05 means the timing beat random timing; a probability of overfitting near 0.5 or above means picking by backtest did no better than picking at random; the rolling column slides the split through the period. What each one asks.

Permutation pProbability of overfittingAcross rolling windows
Momentum0.0700.91depends on the window
MACD0.0260.71depends on the window
Bollinger0.2700.79depends on the window

Hypothetical results on past data (2019-01-02 to 2024-12-31), from a script in the repository that re-runs every figure. Not a recommendation to buy, sell or trade Disney or any other security.

Run it yourself

Each opens in the workspace on Disney over the same dates, straight after sign-up if you are new. Change the ticker or the dates and the numbers change with them, which is the point.

Other US stocks: Apple · Microsoft · Nvidia · Amazon · Alphabet · Meta Platforms · Tesla · JPMorgan Chase · S&P 500 ETF (SPY) · Nasdaq-100 ETF (QQQ) · AMD · Netflix · Berkshire Hathaway · Visa · Bank of America · Walmart · Coca-Cola · Johnson & Johnson · ExxonMobil · Dow Jones ETF (DIA) · Russell 2000 ETF (IWM). All of them.