(Bloomberg) -- Fund managers have been reducing cash holdings to a record low and pouring money into US stocks, triggering a metric that Bank of America Corp. says could be a signal to sell global equities. Most Read from BloombergHow California Sees the World, and ItselfHong Kong's Expat Party Hub Reshaped by Chinese InfluxLondon’s Tube Fares Are Set to Rise by 4.6% Next YearCash as a percentage of total assets under management dropped to 3.9% in December, a move that in the past has been follo