Mean reversion · daily rule · Software & devices
Mayer Multiple on Western Digital
What the play says
WDC with the play, last two years
Shading shows the play's call from the close that triggered it.
Growth of $10,000 since 2005
Log scale. After trading costs, with T-bill interest while out.
The record
The play against buying and holding WDC over exactly the same dates, after costs.
| Play, since 2005 | Hold, since 2005 | Play, 5 yrs | Hold, 5 yrs | |
|---|---|---|---|---|
| Annual return | +23.3% | +20.6% | +72.8% | +56.7% |
| Total return | +9,468% | +5,770% | +1,422% | +834% |
| Worst drawdown | −75.2% | −75.2% | −55.3% | −55.3% |
| Volatility | 47.0% | 47.4% | 52.0% | 53.3% |
| Sharpe ratio | 0.64 | 0.60 | 1.24 | 1.04 |
| Time invested | 100% | 100% | ||
| Switches per year | 0.8 | 0 |
Every call, graded
Right on 18 of 18 closed calls (100%). In calls averaged +357.4%; out calls saw WDC move −5.3% on average.
| Called | Call | Price | Until | WDC moved | Result |
|---|---|---|---|---|---|
| Jun 26, 2026 | IN | $586.26 | now | −35.1% | open |
| Jun 25, 2026 | OUT | $675.17 | Jun 26, 2026 | −13.2% | ✓ right |
| Jun 24, 2026 | IN | $643.62 | Jun 25, 2026 | +4.9% | ✓ right |
| Jun 15, 2026 | OUT | $653.32 | Jun 24, 2026 | −1.5% | ✓ right |
| Jun 4, 2026 | IN | $575.16 | Jun 15, 2026 | +13.6% | ✓ right |
| Jun 3, 2026 | OUT | $593.76 | Jun 4, 2026 | −3.1% | ✓ right |
| May 12, 2026 | IN | $488.46 | Jun 3, 2026 | +21.6% | ✓ right |
| May 11, 2026 | OUT | $515.53 | May 12, 2026 | −5.3% | ✓ right |
| May 7, 2026 | IN | $463.64 | May 11, 2026 | +11.2% | ✓ right |
| May 6, 2026 | OUT | $482.87 | May 7, 2026 | −4.0% | ✓ right |
| Feb 10, 2026 | IN | $262.28 | May 6, 2026 | +84.1% | ✓ right |
| Feb 6, 2026 | OUT | $282.28 | Feb 10, 2026 | −7.1% | ✓ right |
An in call is right when the price rose before the next call; an out call is right when it fell. The latest 12 of 19 calls shown.
How the play works
- In while the close is less than 2.4 times its 200-day average.
- Out when it reaches 2.4 or more.
Mayer used it to decide when to keep buying, not when to sell. Selling above 2.4 is Be The Puck's reading.
On ordinary stocks a price 2.4 times the 200-day is rare, so this is close to buy and hold.
The case against
Valeriy Zakamulin tested moving-average timing on up to 155 years of U.S. stock data and found no statistically significant edge in the second half of that record. The rules earned their keep in a few severe bear markets and lagged buy and hold for long stretches in between.