Bull market

A bull market names a prolonged advance in prices. The widely quoted marker is a rise of twenty percent or more from the most recent low, measured on closing prices, mirroring the convention used for its opposite. As with that threshold, the figure carries no regulatory or academic standing and is applied inconsistently, to different indices, over different windows, and often only once a later high has confirmed it.

Two features of the convention matter more than the number itself. Its arithmetic is asymmetric, because a decline of a given percentage needs a larger percentage rise to undo it, so a recovery to a previous level is always a bigger move than the fall that made it necessary. And the advance is dated from a low that can only be identified once prices have moved away from it, which means the start of a bull market is assigned after the fact, sometimes years after.

The word is also used loosely of sentiment, where bullish means only that a speaker expects a rise. That use reports the speaker rather than the market. Neither use carries information about future prices: a market described as a bull market has risen, which is a statement in the past tense however confidently it is delivered, and the label says nothing about how much of the advance remains.