President Donald Trump's election led to a boom in the stock market and a resulting surge of money into the investment funds.

In fact, since the Republican's victory — Wednesday will mark the one-year anniversary — assets under management for mutual and exchange-traded funds surged about 16 percent, or $2.9 trillion, to $21.1 trillion, according to figures Thomson Reuters released Tuesday.

That total combines inflows and returns, which have been substantial. The Dow industrials are up 29 percent over the past 12 months, while the broader is 21.6 percent higher.

"Performance has been the primary contributor to asset accretion since the 2016 presidential election," Thomson Reuters said in an analysis.

Investors have flocked to funds of almost all stripes since the Trump election, though the balance in absolute cash flow has been to passive funds. While mutual funds, most of which are passively managed, still have far more assets than mostly passively managed exchange-traded funds, the gap is closing.

Since Sept 30, 2016, passive funds have taken in just shy of $686 billion against just $5.2 billion net for active. However, the breakdown is more nuanced, with actively managed bond funds still popular, while investors looking for stock-focused funds prefer passive.