signals / Williams %R cross -20
Williams %R cross -20 is a short-side study. Fires when Williams %R crosses below -20 (leaving overbought).
FAQ
What is Williams %R cross -20?
Williams %R cross -20 is a short-side study. Fires when Williams %R crosses below -20 (leaving overbought).
Which names are firing it?
Among mega-caps in the last 5 daily bars: UNH, V, AMZN, AMZN, TMO, XOM, AMD, NVDA, TSLA, TSLA, AVGO, MSFT.
What is the sample?
Hit rates use the same rank engine as /t/spy on a fixed sample (SPY, SPX, QQQ, IWM, AAPL, MSFT, NVDA, TSLA). 8 of those names have a measurable history for this rule. Windows are 5 days, 1 month and 3 months on daily bars. Last bar in sample: 2026-10-12. Method: /methodology. Caveats: /help.
What does Williams %R cross -20 measure?
Fires when Williams %R crosses below −20 (leaving overbought). Underlying math: see How it works on this page. Catalog line: Fires when Williams %R crosses below -20 (leaving overbought).
What does a firing mean?
A firing is the daily bar where this rule’s condition becomes true (a cross or a flip). It is a study event, not a recommendation to buy or sell. Forward windows on this site are close-to-close with no costs. Study side is short-side (SHORT). A positive forward return is a decline in the close after the print (side-adjusted) — a scoring convention, not a recommendation to sell short. Method: /methodology.
Why can the sample be small?
Hit rates need enough dated prints with a completed forward window. A row with fewer than 10 firings is anecdote, not evidence — the same caveat as /help. Slow rules (especially 50/200 SMA crosses) often have single-digit counts on a two-year tape. We do not invent a hit rate when the count is missing. Names in this sample with a measurable history include NVDA · AAPL · TSLA · IWM.
How it works
Williams %R on daily bars with period 14: %R = −100 × (14-bar high − close) / (14-bar high − 14-bar low). Scale runs from 0 (high) to −100 (low). A firing is a cross of −80 or −20, not a stay inside the zone.
Fires when Williams %R crosses below −20 (leaving overbought).
Definition comes from the rank-rule catalog and the indicator defaults in this repo. Slug williams-r-cross-minus-20 is listed on /api/meta.
How to read it
Study side is short-side (labeled SHORT on firing chips). A positive forward return on this page is a decline in the close after the print (side-adjusted). That is how the event is scored — not a recommendation to sell short. Williams %R is a stochastic-style oscillator inverted to a 0…−100 scale. Crossing −80 / −20 is the same family of “leaving an extreme” event as RSI 30 / 70. Read it as a dated cross, then the side-adjusted forward windows — not as a timing recommendation.
Scoring on this site is shared across every rule (5-day / 1-month / 3-month close-to-close windows, side-adjusted). See How it is scored here below. Names in the tracked sample with a measurable history include NVDA · AAPL · TSLA · IWM. Those figures are the same rows as the hit-rate table below — not a second ranking. Historical hit rates, not a prediction / not trade advice.
When it fails
- Like other oscillators, %R can remain extreme while the trend continues.
- A flat high-low range makes %R jumpy (small denominator).
- −80 / −20 are conventional lines, not fitted parameters.
- Past ≠ future. A historical hit rate is not a prediction and not investment advice.
- No costs modeled. Forward returns are close-to-close with no commissions, slippage or borrow.
- Small samples. A row with fewer than 10 firings is anecdote, not evidence.
- Overlap bias. Clustered prints can credit the same later move more than once.
Same caveats as the rest of the site: /methodology · /help.
How it is scored here
On this site every rule is scored the same way: run it over about two years of daily bars, record each firing, and measure what the name did 5 days, 1 month and 3 months later. Sell signals are measured as shorts, so a positive return is a profitable short (side-adjusted). The composite score is 0.6 × average return + 0.4 × (win rate − 50), with longer horizons weighted more. Nothing here is a forecast.
Full catalog: /signals. Method: /methodology. Slug williams-r-cross-minus-20 is stable and listed on /api/meta.
Same family: Williams %R cross -80
Firing now (mega-caps, last 5 bars)
| Symbol | Last date | Win 1mo | Count |
|---|---|---|---|
| UNH | 2026-10-06Win 57.1% · n=35FIRED | 57.1%n=35 | 35 |
| V | 2026-10-08Win 56.8% · n=37FIRED | 56.8%n=37 | 37 |
| AMZN | 2026-10-12Win 48.8% · n=41STUDY | 48.8%n=41 | 41 |
| AMZN | 2026-10-08Win 48.8% · n=41STUDY | 48.8%n=41 | 41 |
| TMO | 2026-10-06Win 45.0% · n=40STUDY | 45.0%n=40 | 40 |
| XOM | 2026-10-07Win 42.2% · n=45STUDY | 42.2%n=45 | 45 |
| AMD | 2026-10-08Win 45.7% · n=35STUDY | 45.7%n=35 | 35 |
| NVDA | 2026-10-07Win 42.2% · n=45STUDY | 42.2%n=45 | 45 |
| TSLA | 2026-10-12Win 41.9% · n=31STUDY | 41.9%n=31 | 31 |
| TSLA | 2026-10-07Win 41.9% · n=31STUDY | 41.9%n=31 | 31 |
| AVGO | 2026-10-08Win 37.1% · n=35STUDY | 37.1%n=35 | 35 |
| MSFT | 2026-10-08Win 36.1% · n=36STUDY | 36.1%n=36 | 36 |
Hit rates on tracked names
Same rank engine as /t/spy, /t/nvda, and /t/spx, restricted to this rule.
| Symbol | Win 5d | Win 1mo | Win 3mo | Count | Last bar |
|---|---|---|---|---|---|
| TSLA | 34.4% | 41.9%n=31 | 55.6% | 31 | 2026-10-12 |
| MSFT | 43.2% | 36.1%n=36 | 48.4% | 36 | 2026-10-12 |
| AAPL | 48.5% | 41.9%n=31 | 38.5% | 31 | 2026-10-12 |
| QQQ | 28.2% | 39.5%n=38 | 30.6% | 38 | 2026-10-12 |
| NVDA | 43.5% | 42.2%n=45 | 30.8% | 45 | 2026-10-12 |
| SPY | 42.2% | 37.2%n=43 | 24.4% | 43 | 2026-10-12 |
| SPX | 42.2% | 37.2%n=43 | 22.0% | 43 | 2026-10-12 |
| IWM | 34.1% | 40.9%n=44 | 22.5% | 44 | 2026-10-12 |
Honest caveats
- Past ≠ future. Everything here is a historical measurement on daily bars, not a prediction and not investment advice.
- No costs modeled. Forward returns are close-to-close with no commissions, slippage or borrow.
- Overlap bias. Signals that fire in clusters get credit for the same move more than once.
- Small samples. A row with fewer than 10 firings is anecdote, not evidence.
Full method: help manual. Interactive chart: terminal.