Money flowing to stocks globally in just the past five months ($576 billion) has exceeded the inflow seen over the prior 12 years by well over $100 billion, according to data from Bank of America Global Research.
How we got here: Money had consistently flowed out of equity funds as investors sought safety in bonds and money market funds even as stock indexes raced to record highs.
BofA's data show that since 2008 $2.4 trillion has flowed into bonds while just $1 trillion has gone into equities, about half of which has come just this year.
Record sums of cash have flown into equity funds this year with the No. 1 and No. 2 largest inflows to stock funds ever both occurring since the start of February.
What to watch: Investors also are loading up with record leverage, borrowing money against their portfolio holdings at the highest rate since 2007, according to Financial Industry Regulatory Authority data.