Institutional investors — including mutual-fund managers and pension funds — made massive bullish bets on the stock market from late June through the most recent peak in July. According to Lori Calvasina, the head of US equity strategy at RBC Capital Markets, their "euphoric" futures trading was eerily similar to the eves of recent stock-market meltdowns, including the 2008 crisis. She explained why this trend is more sinister than it seems at first glance, and identified a corner of the market that could be relatively insulated from the fallout. Click here for more BI Prime stories.