Spreads indicate the premium investors demand to hold corporate bonds rather than safer government debt.
However, some investors expect credit spreads may widen again to reflect a recession potentially ahead.
Hedge funds and some asset managers short credit, meaning they are betting on a fall in a bond's price, by buying products like credit default swaps (CDS), which rise in value if the risk of a credit default event increases.
Primary markets indicate there is no lack of demand for corporate bonds.
They expect credit spreads to widen in the first half of this year.