As U.S. stock prices tumbled this month, John Sidawi, a fund manager at Federated Hermes, noticed something strange.

The dollar, long a go-to hiding place during market selloffs, wasn’t rallying this time as investors rushed for safety. It was sinking, fast, as hot money poured into gold, the yen, European stocks — almost anywhere but the U.S.

"It’s unusual and very telling,” said Sidawi, who helps oversee bond investments at the firm. "The dollar, in an environment where it should be acting like a safe haven, is not.”