US Treasury yields edge lower after Fitch downgrade

Fitch overnight downgraded the U.S. government's rating to AA+ from AAA, citing an expected fiscal deterioration over the next three years as well as a high and growing general government debt burden. It had placed the rating on watch for a possible cut in May. "This will likely spark risk aversion flows as Asian markets re-open," Tony Sycamore, a markets analyst at IG, wrote in a note to clients.