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What is an all-time high (ATH)?

In one line: An all-time high is the highest price a stock, index, coin or other market has ever traded at in its history.

Trading glossary · Updated 2026-10-21

The short answer

An all-time high (ATH) is the top of a chart's whole history. Above it, there is no older price to look back at.

Indexes like the S&P 500 have set many all-time highs over the decades. Each new one replaces the last.

A simple example

A stock's highest price ever was $150, set two years ago. Since then, it has traded below that.

This week it climbs to $150 again. Two things can happen:

1. It stalls. People who bought at $150 two years ago finally get their money back and sell. The old high acts as Resistance.
2. It breaks through. A candle body closes at $153. Now every person who has ever owned it is sitting on a gain. There are no old sellers left waiting above.

That second case is why traders call it "blue sky." Both are illustrations, not forecasts.

Why it matters

Near an all-time high, the usual way of finding levels runs out. There are no past turning points above price to mark.

So traders lean on other tools:

• The old all-time high itself, which may become Support after a break.
• Round-number levels, like $160 or $200.
• The recent turning points on lower timeframes.

A common mistake

Thinking "it's too high, it must fall." A price being at a record doesn't make it due for a drop. Markets in strong uptrends can set new highs again and again.

The opposite mistake is buying only because it's a record. Price at an all-time high can also reverse sharply. Either way, the chart's turning points tell you more than the label does. Our guide on how to identify a trend covers how to read them.

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