For global stocks, the way down ($15 trillion lost in 7 months) has been much easier than the climb up ($30 trillion added in 4 years).

With markets from Asia to Europe entering bear markets this month, stocks worldwide have lost more than $14 trillion, or 20 percent, in value from a record last June amid worries over global growth and deepening oil declines. The pace of the drop has been so fast that it has already unraveled about half of the rally since a low in 2011.