What is the 200-Day Moving Average? Definition, Formula, and Example
The 200-day moving average is the arithmetic mean of a security's closing prices over the last 200 trading days, used as the standard dividing line between long-term uptrends and downtrends.
What is the 200-Day Moving Average?
The 200-day moving average (200-DMA) is the simple average of a security's closing prices over the most recent 200 trading sessions — roughly 40 weeks, or about ten calendar months of market activity. It is the single most-watched trend filter in global markets. Price above the 200-DMA defines a long-term uptrend; price below it defines a long-term downtrend. Institutional desks, pension rebalancers, CTAs, and retail chartists all track the same line, which is precisely why it works: the level is a coordination point where real money changes behavior. When a major index crosses its 200-day, it is front-page news and a trigger for billions in systematic flows.
How the 200-Day Moving Average is Calculated
200-DMA = (Sum of the last 200 closing prices) ÷ 200
Each new session, the oldest close drops off and the newest close enters, so the average "moves." Key properties:
- It is a simple moving average — every one of the 200 closes carries equal weight of 0.5%.
- Because the lookback is long, the line is smooth and slow: a single day's close moves the 200-DMA by only (today's close − the close 200 days ago) ÷ 200.
- The slope of the line matters as much as price relative to it. A rising 200-DMA confirms trend health; a flat or falling line signals deterioration even while price sits above it.
Variants include the 200-day exponential moving average, which weights recent prices more heavily and reacts faster, and the 40-week moving average, its weekly-chart equivalent.
Worked Example
Consider NVDA through its 2022–2023 cycle. NVIDIA peaked near $346 (split-adjusted ~$34.60) in November 2021, broke decisively below its 200-DMA in January 2022, and stayed below it for the entire bear phase, bottoming near $112 (~$11.20 split-adjusted) in October 2022 — a 68% drawdown. The stock reclaimed its 200-day moving average in January 2023 around $185, with the line itself flattening and then turning up by March. That reclaim, confirmed by the slope turning positive, marked the regime shift: NVDA never traded below its 200-DMA again during the subsequent run past $1,200 (pre-split). A trader using the 200-DMA as a regime filter was out of the name for the worst of 2022 and back in for the AI-driven advance.
When Traders Use the 200-Day Moving Average
- Regime filter: The classic rule — hold equities only above the 200-DMA, move to cash or hedges below it — historically sidesteps the deepest parts of bear markets at the cost of whipsaws in ranges.
- Support/resistance: In uptrends, pullbacks to a rising 200-DMA are standard institutional accumulation zones; the first touch after a long run above is watched by every desk.
- Cross signals: The 50-day crossing above the 200-day is the golden cross; crossing below is the death cross.
- Systematic allocation: Trend-following CTA programs anchor on 200-day and similar lookbacks, meaning breaks generate mechanical, price-insensitive selling and buying.
Limitations and Common Misconceptions
The 200-DMA is a lagging indicator by construction — at a major top, price can fall 15–20% before the line is breached, and at bottoms it keeps you out through the first leg of recovery. In sideways markets it generates repeated false signals; 2015–2016 and 2023's chop produced multiple whipsaw crosses. There is also nothing magic about 200: 180, 200, and 250-day lines produce nearly identical results, and the level "works" largely because of reflexivity — enough participants watch it that their orders cluster there. Finally, the 200-DMA tells you nothing about valuation, earnings, or risk; it is a trend description, not a forecast.