Some Investors Are Missing Out on Higher Yields—and Don’t Know It

Stocks and bonds both fell sharply last year. But one bright spot in financial markets was the rising interest rates on money-market funds, which in December topped 4% on average for the first time in 15 years.

Money-fund rates have stayed high so far this year, now averaging 4.18%, according to Crane Data LLC. That’s a big increase from just a few months ago, and investors who aren’t aware of the climb in rates—or who don’t act on it—could be missing out on an opportunity for much higher returns than they’re getting now on the cash in their brokerage accounts.