Traders work on the floor of the New York Stock Exchange.

The strong stock market performance to start 2019 has yet to lure most investors back in from the sideline, implying that more gains could be ahead, according to a closely followed survey of professional investors.

Even with the Dow Jones Industrial Average up more than 11 percent year to date, the allocation to global stocks among respondents to the March Bank of America Merrill Lynch Global Fund Manager Survey fell to its lowest since October 2016 at just 3 percent overweight.

Hedge fund managers in particular are at their lowest net allocation to equities since December 2016, with the trend among all investors toward more defensive positions.

"The pain trade for stocks is still up," Michael Hartnett, chief investment strategist at BofAML Data Analytics, said in a statement. "Despite rising profit expectations, lower rate expectations and falling cash levels, stock allocations continue to drop. There is simply no greed to sell in equities."