Breakouts & channels · daily rule · Software & devices
P&F Double Top 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 | +14.8% | +20.6% | +42.5% | +56.7% |
| Total return | +1,891% | +5,770% | +482% | +834% |
| Worst drawdown | −74.5% | −75.2% | −54.1% | −55.3% |
| Volatility | 33.6% | 47.4% | 40.5% | 53.3% |
| Sharpe ratio | 0.52 | 0.60 | 0.98 | 1.04 |
| Time invested | 58% | 100% | ||
| Switches per year | 8.0 | 0 |
Every call, graded
Right on 63 of 175 closed calls (36%). In calls averaged +7.2%; out calls saw WDC move +2.6% on average.
| Called | Call | Price | Until | WDC moved | Result |
|---|---|---|---|---|---|
| Sep 14, 2026 | OUT | $426.94 | now | −10.8% | open |
| Sep 8, 2026 | IN | $477.30 | Sep 14, 2026 | −10.6% | ✕ wrong |
| Aug 24, 2026 | OUT | $435.24 | Sep 8, 2026 | +9.7% | ✕ wrong |
| Aug 12, 2026 | IN | $453.95 | Aug 24, 2026 | −4.1% | ✕ wrong |
| Aug 6, 2026 | OUT | $451.38 | Aug 12, 2026 | +0.6% | ✕ wrong |
| Jul 31, 2026 | IN | $544.66 | Aug 6, 2026 | −17.1% | ✕ wrong |
| Jun 26, 2026 | OUT | $586.26 | Jul 31, 2026 | −7.1% | ✓ right |
| May 26, 2026 | IN | $524.35 | Jun 26, 2026 | +11.8% | ✓ right |
| May 18, 2026 | OUT | $458.41 | May 26, 2026 | +14.4% | ✕ wrong |
| Apr 6, 2026 | IN | $303.97 | May 18, 2026 | +50.8% | ✓ right |
| Mar 23, 2026 | OUT | $294.62 | Apr 6, 2026 | +3.2% | ✕ wrong |
| Mar 10, 2026 | IN | $266.06 | Mar 23, 2026 | +10.7% | ✓ 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 176 calls shown.
How the play works
- In on a double-top breakout: the current X column rises at least one box above the top of the previous X column.
- Out on a double-bottom breakdown: the current O column falls at least one box below the bottom of the previous O column.
- Otherwise the rule keeps the chart's last signal.
Boxes are 2% apart, and a new column needs a 3-box reversal (about 6%). Dorsey's classic box table uses fixed price bands; ChartSchool's examples use 1% boxes.
The chart is built from daily highs and lows by StockCharts' high-low method: a new box from the high wins, and the low only counts if it reverses the column.
The signal fires on the day the breakout box fills during the day. Be The Puck acts on that day's close.
Where the rules come from
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.