(Reuters) - U.S. high yield corporate bond spreads surged to 401 basis points as of late Thursday, their highest since November 2023, as global markets swooned over fears that U.S. President Donald Trump's plan for import tariffs would kick off a trade war.

The options adjusted spread on the ICE BofA High Yield Index, which measures the difference in yields between junk bonds and Treasury debt rose from 342 basis points on Wednesday, while spreads on investment grade bonds rose to 106 bp, the highest since August 2024, from 96 bp.