For US credit markets now, the party is far from over, and money keeps pouring in.

Risk premiums have been shrinking for most of the year, even if they edged higher in the latest week. The extra yield that investors demand for buying junk bonds instead of high-grade debt has been shrinking, signaling less fear of default. A key measure of that gap was just 1.02 percentage point on Thursday, according to data compiled by Bloomberg, close to the lowest in about two years.