Does the Money Flow Index strategy beat buy & hold on Costco? (COST · backtested honestly)
The Money Flow Index is a volume-weighted RSI: it weights each day's typical price by volume, then gauges how stretched buying pressure is versus selling on a 0-100 scale.
Over this period, Money Flow Index on Costco returned +23.4%, while simply buying and holding returned +116.8% — it lagged buy & hold by 93.4 points, with a worst drawdown of -31.4%. It traded 5 times and sat in cash about 76% of the time. It's a mechanism you test — not a recommendation.
It lagged buy & hold over this window — that's a result, and a backtest you can kill for free just did its job. Re-tuning this same idea until it looks better only adds another shot at looking good by luck, so the honest next move is a fresh one: test a different strategy on Costco, or build your own — free. Most ideas die cheaply right here, and that's exactly how the rare one that holds up gets found.
Or stop here — walking away from an idea that didn't beat simply holding is a result, not a failure.
Run it yourself
Change the parameters and the window, then re-run — no account needed.
Change the rules? Open the Money Flow Index rules on Costco in the no-code builder — the same rules tested here — and make them your own.
Open in the builder →A live badge that re-runs itself and links back here. Free to embed on any blog, newsletter or forum — it shows the honest result, beat or lagged.
<iframe src="https://stratsemble.com/embed/costco-mfi-backtest" width="360" height="340" style="border:0;border-radius:12px;max-width:100%" loading="lazy" title="Does the Money Flow Index strategy beat buy & hold on Costco?"></iframe>- • The strategy line is Money Flow Index on Costco; the dashed line is simply buying and holding COST. Beating the dashed line is the whole point — many strategies don't.
- • Max drawdown is the worst peak-to-trough fall you'd have sat through. A higher return with a much deeper drawdown is not obviously better.
- • Every fill assumes next-open execution with costs & slippage on — no acting on prices you couldn't have known.
- • A small number of trades means a small sample. Treat a great-looking result on a handful of trades with suspicion.
This is a hypothetical backtest of a well-known mechanism on past data. It is not advice, not a prediction, and not a claim that the strategy works. I hold no funds and place no orders. The value here is the ability to test an idea honestly — see where it would have helped, and where it would have hurt — before you ever risk real money on your own broker.
How this is computed → · who's behind it · where a backtest fits
See what actually beats buy & hold — most don't, here are the rare few that do →