Long touted as hands-down the world's "safe haven" securities, the behavior of U.S. Treasuries during and after the COVID-19 pandemic calls that label into question, suggesting they are little different from the debt issued by the likes of Germany, Britain, France, or even big corporations.

That's the key finding of new research presented at the Kansas City Fed's annual research conference in Jackson Hole, Wyoming. It examines a shift in investor behavior in that period that raises questions about the "exorbitant privilege" the U.S. government has long enjoyed to borrow broadly on the global market even as federal budget gaps grow ever wider.