Unum Group Chief Executive Officer Thomas Watjen is shying awayfrom adding junk bonds to the insurer's investment portfolio afteryields plummeted.

“There are times like now maybe where high-yield gets too hot,”Watjen, whose company holds about $40 billion of fixed- maturitysecurities, said today in an interview at Bloomberg headquarters inNew York. “You just can't get enough return in the sector tojustify investing, given the risk parameters of that assetclass.”

Yields on speculative-grade debt tumbled to a record low of 7.19percent in May before rising to 7.45 percent as of July 22,according to Bank of America Merrill Lynch index data. Thatcompares with an average borrowing cost of 12.6 percent onsimilarly rated companies two years earlier, the data show.