Moving Average

A moving average is among the oldest and most widely referenced tools in technical analysis. It works by summing the closing prices of a security over a defined look-back window — for example, 50 days or 200 days — and dividing by the number of periods in that window. Each day, the oldest data point drops out and the newest one is added, so the average 'moves' forward through time.

There are two primary variants. The simple moving average (SMA) weights all periods equally. The exponential moving average (EMA) applies progressively greater weight to more recent prices, making it more responsive to recent price changes. Other variants include the weighted moving average (WMA) and the hull moving average, each designed to balance smoothness against responsiveness in different ways.

Historically, analysts have studied moving averages in relation to actual price action to characterize trend direction. When a security's price has historically traded above a rising long-term moving average, such observations have often been associated with periods of sustained upward price momentum in historical data. Conversely, prices persistently below a declining moving average have historically characterized downtrending markets in many studied securities. These are historical observations about how past price data has behaved relative to these averages; they do not constitute predictions of future performance.

Two specific moving average relationships that technical analysts frequently observe are the 'golden cross' and the 'death cross.' A golden cross refers to the historical observation when a shorter-term moving average (commonly the 50-day SMA) crosses above a longer-term moving average (commonly the 200-day SMA). A death cross refers to the reverse crossing. Academic research on these signals has produced mixed results, and their historical associations with subsequent price behavior vary significantly depending on the security, time period, and market environment studied.

Moving averages are also used in the construction of other technical indicators, including the MACD and Bollinger Bands. Like all technical indicators, moving averages are mathematical summaries of historical price data. Their value lies in organizing and visualizing past price behavior; they do not have predictive power in any scientific sense, and no technical indicator can reliably forecast future prices.