"We spend too much time talking about market timing," said Fink, co-founder of the world's largest money manager. "The key for investors is to stay in the market. ... You should be 100 percent in equities."
Fink said he's not sure what "inning we're in" regarding the economic cycle. But he said the tax cut from President Donald Trump and Republicans has extended cycle.
The stock market reached record heights on Jan. 26 before tanking into correction territory and ushering in a period of wild swings.
Since the Feb. 9 intraday low, the S&P 500 has gained 4.3 percent. However, the index was still nearly 1.2 percent lower for 2018 as of Wednesday's close.
Assets under management increased slightly from the fourth quarter to just over $6.3 trillion as of the end of March. While a huge number, it was short of expectations.