Why are bitcoin bear markets different?
Because 20% declines are too common.
Bitcoin is historically a highly volatile asset, which means the bear market threshold often used by traditional markets (i.e., a 20% decline over at least two months) is not useful for confirmation that bitcoin has entered a bear market phase.
Throughout bitcoin’s short history, there have been 14 months, 24 weeks, and 19 days that — measured from open to close — had price declines of -20% or worse. That’s a lot of “bear markets” according to the traditional definition.
As shown in the data indexed on this site, periods of bitcoin’s history that are widely recognized as bear markets generally include drawdowns of at least 60% that last about 90 days or more. Even though it only lasted 88 days, this site indexes the first drawdown in 2013 because the decline was severe and its duration can easily be rounded up by two days.