The whole system
A golden cross happens when the 50-day moving average crosses above the 200-day moving average. The reverse, the 50 crossing below the 200, is called a death cross. The strategy is simply to be long after a golden cross and flat after a death cross. That's it. Two lines, two signals, no discretion.
| Rule | Definition |
|---|---|
| Entry | 50-day SMA closes above the 200-day SMA → buy at the next open |
| Exit | 50-day SMA closes below the 200-day SMA → sell at the next open |
| Universe | Broad index ETFs or large, liquid instruments |
| Position size | Fixed fraction of account; see the 1% rule |
| Frequency | Signals arrive roughly every one to two years on an index |
SMA = simple moving average. Educational summary, not investment advice.
Why it works, when it works
The golden cross is a slow, deliberate way of saying "the intermediate trend has turned up and stayed up." Because the 50-day must drag itself across the 200-day, a single sharp rally can't trigger it; the move has to persist for weeks. That persistence is what filters noise from trend. The cost, as with every trend filter, is lag: the signal fires long after the bottom, and exits fire long after the top.
On major stock indexes the record is respectable: golden-cross periods have historically captured most of the market's gains while death-cross periods contain most of its catastrophes. On individual stocks the results are far noisier: single names gap and reverse too fast for 200 days of smoothing to keep up.
How people ruin it
- Optimizing the numbers. 43/187 backtests better than 50/200 on your data? That's curve fitting, not discovery. The exact lengths barely matter; the structure does.
- Trading every cross on every ticker. The signal is designed for broad, trending instruments. Applying it to a meme stock is using a seatbelt as a bungee cord.
- Overriding exits. The death cross will sometimes sell what later recovers. Taking the signal anyway is the whole discipline; the one bear market it saves you from pays for a decade of small regrets.
- Going short on death crosses. Historically the market still drifts up, on average, below the cross. Flat is the position.
A sensible way to run it
Pick one or two broad index ETFs. Check the averages once a week; weekly is plenty. When the cross happens, act at the next open, size the position by rule, and write the trade down in your journal. Then go live your life. A strategy that signals once a year is not supposed to be entertaining. For the deeper evidence on why slow trend systems endure, Andreas Clenow's Following the Trend is the standard reference.
Prefer strength to smoothing?
Momentum traders skip the averages entirely and just buy what's already winning.