The stock market has risen even as forecasts for economic growth have shown concern about a slowdown. Economists expect that the United States grew at an annualized pace of less than 2 percent in the first quarter, a slowdown from the 3 percent growth posted in 2018.

And stock analysts have continued to downgrade their expectations for profits this year. Since the end of 2018, full-year profit estimates for companies in the S&P 500 have declined 3 percent, according to FactSet, a financial data provider.

Investors who have so far sat out the 2019 rally, because of concerns about the economy or profits, may be coming around to the idea that it is a mistake to do so when the Fed is so clearly the primary driver of gains.

Last week, more than $25 billion surged into funds that buy American stocks, according to data from EPFR Global, a firm that tracks mutual funds and exchange-traded funds.

“It could be that the chase is on,” said Michael Hartnett, chief investment strategist at Bank of America Merrill Lynch. “People could be suddenly saying, ‘I’ve got to get involved.’”