June has been the worst month for U.S. corporate bonds since the start of the pandemic by at least one measure, but investors like TCW Group Inc. and Voya Investment Management think it's too soon to hunt for bargains.

Many credit investors are hoarding cash as the Federal Reserve tightens aggressively, having lifted rates this week by the most since 1994, with a goal of taming inflation. They're hesitating to buy even after junk bonds have dropped 5.7 percent in June through Thursday, on track for their worst month since March 2020. Risk premiums on U.S. high-grade corporate bonds are climbing toward their highest levels in about two years.

"We're not looking to add outright at these levels," said Travis King, head of U.S. investment-grade corporates at Voya. The chance of a recession is rising, and current corporate debt prices don't adequately reflect the risk, he said. His cash and Treasuries levels are 25 percent to 50 percent higher than normal.