Investors ended a 3-week retreat from Wall Street last week by sending nearly $8.6 billion into mutual funds and exchange-traded funds that hold U.S. stocks, according to data released Wednesday by the Investment Company Institute.

The $8.6 billion in inflows was the largest net gain for U.S. stock funds since mid-June and came as China announced tariff exemptions on a basket of U.S. goods, igniting investor hopes that the trade war between the world's two largest economies could be resolved.

Despite last week's gains, U.S. stock funds have lost nearly $89 billion in net outflows since the start of the year.

Those losses have come amid a rally that has pushed the benchmark S&P 500 index up nearly 20% year-to-date. Bond funds, meanwhile, brought in slightly more than $13 billion last week, the largest single-week gain since February.

Those inflows continued a streak that has swelled the category by nearly $303 billion in assets since the start of the year. World stock funds lost slightly more than $1 billion last week, bringing the year to date loss for the category to $34.3 billion.