Volume & money flow · daily rule · Healthcare
Money Flow Index on Boston Scientific
BSX 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 BSX over exactly the same dates, after costs.
| Play, since 2005 | Hold, since 2005 | Play, 5 yrs | Hold, 5 yrs | |
|---|---|---|---|---|
| Annual return | −4.8% | +1.1% | −10.0% | +0.7% |
| Total return | −65% | +26% | −41% | +4% |
| Worst drawdown | −80.2% | −85.9% | −59.4% | −61.5% |
| Volatility | 25.1% | 32.4% | 20.1% | 26.6% |
| Sharpe ratio | −0.14 | 0.14 | −0.61 | 0.02 |
| Time invested | 42% | 100% | ||
| Switches per year | 1.5 | 0 |
Every call, graded
Right on 17 of 32 closed calls (53%). In calls averaged −4.6%; out calls saw BSX move +16.8% on average.
| Called | Call | Price | Until | BSX moved | Result |
|---|---|---|---|---|---|
| Aug 20, 2026 | OUT | $49.37 | now | −12.3% | open |
| Sep 23, 2025 | IN | $97.69 | Aug 20, 2026 | −49.5% | ✕ wrong |
| Aug 16, 2022 | OUT | $42.35 | Sep 23, 2025 | +130.7% | ✕ wrong |
| May 14, 2021 | IN | $41.55 | Aug 16, 2022 | +1.9% | ✓ right |
| Dec 21, 2020 | OUT | $34.82 | May 14, 2021 | +19.3% | ✕ wrong |
| Sep 24, 2020 | IN | $37.12 | Dec 21, 2020 | −6.2% | ✕ wrong |
| Apr 15, 2020 | OUT | $34.79 | Sep 24, 2020 | +6.7% | ✕ wrong |
| Oct 11, 2019 | IN | $38.23 | Apr 15, 2020 | −9.0% | ✕ wrong |
| Jun 11, 2019 | OUT | $41.17 | Oct 11, 2019 | −7.1% | ✓ right |
| Dec 26, 2018 | IN | $33.68 | Jun 11, 2019 | +22.2% | ✓ right |
| Apr 19, 2018 | OUT | $28.89 | Dec 26, 2018 | +16.6% | ✕ wrong |
| Dec 11, 2017 | IN | $25.50 | Apr 19, 2018 | +13.3% | ✓ 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 33 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.