The note from UBS Evidence Lab shows private bankruptcy filings in 2023 have exceeded the highest point recorded during the early stages of the COVID pandemic by a considerable amount. The four-week moving average for private filings in late February was 73 percent higher than in June 2020.

"[We] believe one of the more underappreciated signs of distress in U.S. corporate credit is already emanating from the small- and mid-size enterprises sector," Matthew Mish, head of credit strategy at UBS, wrote in a recently published research note. "[The] smallest of firms [are] facing the most severe pressure from rising rates, persistent inflation and slowing growth."

Industries hit hardest by the wave of bankruptcies include real estate, health care, chemicals, and retail outlets, according to the Swiss Bank's report.

The Federal Reserve's monetary tightening to combat inflationary pressures has been largely behind the uptick in bankruptcies. UBS indicated that the fear of a credit crunch has further worsened the rise in defaults.

Credit conditions are tightening across the spectrum. Large businesses and individual borrowers are feeling the heat as well.