Volume & money flow · daily rule · Software & devices
Money Flow Index on Western Digital
WDC with the play, last two years
Shading shows the play's call from the close that triggered it.
Money Flow Index (14)
Dashed lines at 20, 80.
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 | −1.3% | +20.6% | −2.4% | +56.7% |
| Total return | −25% | +5,770% | −11% | +834% |
| Worst drawdown | −68.9% | −75.2% | −58.4% | −55.3% |
| Volatility | 26.8% | 47.4% | 30.3% | 53.3% |
| Sharpe ratio | 0.02 | 0.60 | −0.05 | 1.04 |
| Time invested | 38% | 100% | ||
| Switches per year | 1.1 | 0 |
Every call, graded
Right on 11 of 24 closed calls (46%). In calls averaged +0.4%; out calls saw WDC move +35.6% on average.
| Called | Call | Price | Until | WDC moved | Result |
|---|---|---|---|---|---|
| May 21, 2025 | OUT | $49.25 | now | +673.0% | open |
| Jan 3, 2025 | IN | $48.19 | May 21, 2025 | +2.2% | ✓ right |
| May 31, 2023 | OUT | $29.13 | Jan 3, 2025 | +65.4% | ✕ wrong |
| Mar 16, 2023 | IN | $26.58 | May 31, 2023 | +9.6% | ✓ right |
| Jan 17, 2023 | OUT | $28.07 | Mar 16, 2023 | −5.3% | ✓ right |
| Jun 23, 2021 | IN | $52.08 | Jan 17, 2023 | −46.1% | ✕ wrong |
| Jan 6, 2020 | OUT | $47.05 | Jun 23, 2021 | +10.7% | ✕ wrong |
| Nov 20, 2019 | IN | $35.73 | Jan 6, 2020 | +31.7% | ✓ right |
| Jul 16, 2019 | OUT | $37.59 | Nov 20, 2019 | −5.0% | ✓ right |
| Sep 12, 2018 | IN | $39.50 | Jul 16, 2019 | −4.8% | ✕ wrong |
| Mar 15, 2018 | OUT | $70.54 | Sep 12, 2018 | −44.0% | ✓ right |
| Aug 8, 2017 | IN | $55.46 | Mar 15, 2018 | +27.2% | ✓ 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 25 calls shown.
How the play works
- In when the 14-day MFI crosses up through 20.
- Out when it crosses down through 80.
The creators also stress divergences, which this rule ignores.
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.