Oversold

Oversold is a technical analysis term for an asset whose price has dropped sharply over a short period, to the point where momentum indicators show readings that have often preceded a rebound or at least a slowdown in the fall. It suggests that sellers may be running out of steam, not that the asset is cheap or that a recovery is certain.

Common oversold signals include a relative strength index below 30 and a stochastic oscillator below 20. The term is the mirror image of overbought. It describes the speed of a recent decline, which is different from "undervalued", a judgement about price compared with an asset's fundamentals.

Picture a crowded shop during a fire drill. Everyone rushes for the exit at once, and for a few minutes the shop is almost empty. That does not mean the shop has closed for good; once the panic passes, some customers usually wander back. An oversold reading says the rush for the exit has been unusually intense.

The risk is that sometimes the alarm is real. A falling price can keep falling, and buying simply because a chart says "oversold" is often compared to trying to catch a falling knife.

The stochastic oscillator, popularised by George Lane in the 1950s, shows where the latest closing price sits within the range of recent highs and lows. Its main line, called %K, is calculated as:

• $C$ is the most recent closing price.
• $L_{n}$ is the lowest price over the last $n$ periods, usually 14.
• $H_{n}$ is the highest price over the same periods.

A reading below 20 is usually treated as oversold. Suppose a coin's 14-day high is 70 dollars, its 14-day low is 50 dollars and it closes at 52 dollars. Then %K = (52 − 50) ÷ (70 − 50) × 100 = 2 ÷ 20 × 100 = 10. The close sits near the bottom of its recent range, so the reading is oversold. An RSI below 30, or a price below the lower of the Bollinger Bands, gives a similar signal.

• Looking for entries. Some traders treat oversold readings as a cue to watch for a bounce, often waiting for the indicator to climb back above its threshold before acting.
• Bullish divergence. A common setup is price making a new low while the oscillator makes a higher low, which suggests the decline is slowing.
• Covering shorts. Traders who profited from short selling may take profits when a market becomes deeply oversold, which can itself fuel a rebound.
• Lowering thresholds. In strong downtrends, some analysts move the oversold line to 20 on the RSI, because readings below 30 become routine.

The logic behind these signals is mean reversion, the assumption that prices which move far from their recent average tend to drift back toward it. That assumption works reasonably well in markets moving within a range, where buyers and sellers repeatedly step in at familiar levels. It works poorly when a market is in a sustained trend, because the average itself keeps moving lower and each "oversold" price is soon followed by another. For this reason, many traders first decide whether a market is trending or range-bound, and only lean on oversold readings in the second case.

Extreme oversold readings often coincide with capitulation, the point at which many holders give up and sell regardless of price, typically on very high volume. In crypto, such moments are often accelerated by cascading liquidations of leveraged long positions. Sharp rebounds can follow, but a short-lived recovery inside a continuing decline, known as a dead cat bounce, is also common. During a bear market, an asset can register oversold readings repeatedly on the way down. Traders often look for confirmation from volume indicators such as on-balance volume before treating an oversold reading as meaningful.

Oversold readings measure recent price behaviour only. They cannot detect problems such as a failing project, a hack, an exchange collapse or regulatory action, any of which can push a price far lower than past patterns suggest. Thresholds are conventions, and results change with the time frame and settings chosen. Buying assets solely because they are oversold has produced heavy losses in markets where the fundamental story had changed. Like its counterpart, oversold is a descriptive signal that works best alongside trend, volume and fundamental analysis, and it is not advice to buy.