INDICATOR EXPLAINER · #05
S&P vs 200-day MA — the trend line everyone watches
The 200-day moving average is the most-watched trend line in finance. But the data reveals something the folklore gets wrong — far above the 200-day is NOT the same as overbought.
Today's reading
Same number you'll see on this component's card on the main dashboard.
What is the 200-day moving average?
The 200-day moving average is exactly what it sounds like: the average of the S&P 500's closing prices over the last 200 trading days (roughly a full calendar year of trading). Because it smooths out day-to-day noise, it's used as a rough marker of the long-term trend.
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Above the 200-day MA — the market is generally
considered to be in an uptrend.
Below the 200-day MA — the market is generally considered to be in a downtrend.
Distance from the MA tells us how "stretched" the market is — either extended in a rally, or crashed below trend.
An important quirk: the S&P 500 has an upward long-term drift, so it spends most of its time above its 200-day MA. Over 1990–2026, the median distance is +4.7% above the MA. "Zero distance" is not neutral — it's actually mildly bearish.
How BATS uses it
Same direction convention as our other components: far below the MA = LOW BATS (oversold buy signal), far above the MA = HIGH BATS. The scoring is piecewise linear and centered on the historical median (+5%) rather than zero, so the "Neutral" bucket matches what a healthy uptrend actually looks like.
| Distance from 200-day MA | BATS points | Bucket |
|---|---|---|
| Below −15% | 5 | Extremely Oversold |
| −15% to −5% | 5 – 30 | Oversold |
| −5% to +5% | 30 – 50 | Slightly Bearish → Neutral |
| +5% to +10% | 50 – 70 | Slightly Bullish |
| +10% to +15% | 70 – 90 | Bullish |
| Above +15% | 95 | Extended |
Does it work? — Historical backtest (1990–2026)
For every trading day since 1990 with a full 200-day window behind it, we compute the S&P's distance from its 200-day MA and measure how the S&P 500 actually performed 6 and 12 months later.
What the data actually says
Three findings from the 36-year backtest — and finding #2 is a big one:
Deep below the MA = buying opportunity.
When the S&P was more than 12% below its 200-day MA (n=381), forward 12-month returns averaged +18.7%, with 81% positive. This bucket includes the 2008 crash lows, the 2020 COVID panic, and other major mean-reversion setups.
Takeaway: When the market has fallen well below trend, history says the odds favor patient buyers.
Far ABOVE the MA is NOT overbought.
When the S&P was more than 12% above its 200-day MA (n=334), forward 12-month returns averaged +14.5%, with a stunning 98% hit rate — the highest of any bucket on any component we've backtested. Extreme uptrends have historically continued, not reversed.
Takeaway: The old rule "far above the 200-day = time to sell" is not supported by the data. Strong trends deserve respect, not skepticism.
The real warning zone is "somewhat below."
When the S&P sat between 6% and 12% below its 200-day MA — falling, but not yet a crash — forward 12-month returns averaged only +2.0%, with just 53% positive. This is the worst forward-return bucket we've found on any component.
Takeaway: A moderately broken uptrend is a much worse setup than a full crash. Either wait for capitulation (below −12%) or a return to trend (above the MA).
How to use this information
- Respect strong trends. When the S&P is far above its 200-day, don't sell just because it feels "extended." History says extreme uptrends have continued 98% of the time over the next 12 months.
- Look for the deep-below signal. Buying when the S&P is 12%+ below its 200-day has historically been rewarded — +19% average forward 12mo. But it's rare (only ~4% of days), so you'll wait a long time between opportunities.
- Beware the "moderately down" zone. When the S&P is 6–12% below its 200-day, the forward-return odds are the worst of any zone. This is not a buying opportunity yet — it's a warning that the downtrend may still have room to run.
- Combine with other components. MA200 is a trend measure. Blended with VIX (fear), Breadth (participation), RSI (momentum), and Junk Bond Demand (credit), the BATS captures more of the picture than any single indicator alone.
Reminder: None of this is investment advice. Historical patterns are not guarantees. Always do your own research or talk to a financial professional.