Stocks have been having a good run again recently.
The Standard & Poor's 500 rose 1.8 percent last week to close at a new high. The Nasdaq Composite jumped 3.3 percent to wipe out its losses since the dot-com bubble and hit a record high.
However, strategists at Bank of America Merrill Lynch sounded a note of caution last week.
They said in a note on Thursday that even as US stock markets have been making record highs, investors have been pulling money out of US stock funds.
“Correction risks will grow in [the] absence of fresh inflows in coming weeks,” wrote the strategists.