Fund managers who manage volatility by rapidly switching their portfolio between cash and equities will sell off $225 billion of stocks over the next few days, Barclays told clients. Barclays also told clients that the spike in the VIX index — the S&P 500's fear gauge — was "technical in nature and does not necessarily indicate a true increase in risk perception. "  LONDON — Fund managers who manage volatility by rapidly switching their portfolio between cash and equities will be forced to sell around $225 billion of stocks over the next few days, Barclays told clients.