signals / EMA 9/21 death cross
EMA 9/21 death cross is a short-side study. Fires when the 9-day EMA crosses below the 21-day EMA.
FAQ
What is EMA 9/21 death cross?
EMA 9/21 death cross is a short-side study. Fires when the 9-day EMA crosses below the 21-day EMA.
Which names are firing it?
Among mega-caps in the last 5 daily bars: CVX.
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 EMA 9/21 death cross measure?
Fires when the 9-day EMA crosses below the 21-day EMA. Underlying math: see How it works on this page. Catalog line: Fires when the 9-day EMA crosses below the 21-day EMA.
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 IWM · TSLA · AAPL · MSFT.
How it works
Two exponential moving averages of the daily close: EMA 9 and EMA 21, span smoothing, adjust=False. The rule is a cross of those two averages — not price versus EMA.
Fires when the 9-day EMA crosses below the 21-day EMA.
Definition comes from the rank-rule catalog and the indicator defaults in this repo. Slug ema-9-21-death-cross 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. A 9/21 EMA cross is a short-horizon trend event. It will print more often than a 50/200 SMA cross. More prints help the sample size and also include more chop. Read the 5-day window separately from the 3-month window; they answer different questions.
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 IWM · TSLA · AAPL · MSFT. 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
- Short EMAs cross often in a range; many 9/21 prints are chop.
- Both sides of the pair (golden and death) can fire in the same swing.
- EMA span smoothing is not the same as Wilder alpha smoothing used on RSI / ADX.
- 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 ema-9-21-death-cross is stable and listed on /api/meta.
Same family: EMA 9/21 golden cross
Firing now (mega-caps, last 5 bars)
| Symbol | Last date | Win 1mo | Count |
|---|---|---|---|
| CVX | 2026-10-07Win 61.5% · n=13FIRED | 61.5%n=13 | 13 |
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 | 26.7% | 57.1%n=14 | 50.0% | 14 | 2026-10-12 |
| AAPL | 45.5% | 54.5%n=11 | 30.0% | 11 | 2026-10-12 |
| NVDA | 29.4% | 43.8%n=16 | 33.3% | 16 | 2026-10-12 |
| QQQ | 30.8% | 33.3%n=12 | 27.3% | 12 | 2026-10-12 |
| SPX | 10.0% | 30.0%n=10 | 37.5% | 10 | 2026-10-12 |
| SPY | 18.2% | 27.3%n=11 | 33.3% | 11 | 2026-10-12 |
| IWM | 50.0% | 62.5%n=8 | 50.0% | 8 | 2026-10-12 |
| MSFT | 33.3% | 44.4%n=9 | 50.0% | 9 | 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.