The most common definition of a bull market is when a security rises 20 percent from a bear-market low.
Stock-market indexes, single stocks, commodities and all other types of financial instruments can experience one. A new bull market is born out of the ashes of a bear market, or a decline of at least 20 percent from a peak.
While bull markets typically occur during periods of economic growth, they are often born when the economy appears weak. That’s because the stock market is forward-looking, often six or 12 months into the future.
Excluding the current bull market, there have been 26 bull markets in the history of the S&P 500, according to Dow Jones Market Data.
They have no set length as their duration depends on a number of factors including the economy and decisions specific to a company or industry.
The average bull market has lasted 720 trading days and returned 113 percent, the data showed. As a reference, there were 252 trading days last year.