From FT.com:

“People have taken their fixed income allocations and turned them into credit allocations because they are scared of rising rates,” says Ashish Shah, head of fixed income at AllianceBernstein. But the creditworthiness of a company behaves similarly to assessing whether to buy stock in a company, he adds. “So their stock and bond portfolios are becoming stock and credit portfolios, which in the way I think about it is just stock and stock.” And with many investors worried about a peak in equity markets around the corner, Mr Shah finds that disconcerting. “When investors now look at their portfolio, they don’t have anything that does well when stocks sell off.”