Investors remained gripped on Thursday by lenders’ attempts to sell more than $1bn of US subprime mortgage assets seized from two stricken Bear Stearns hedge funds, driving credit markets lower amid fears of a broader repricing of risky debt securities.

If sustained, the fall-out could make it more expensive for companies to raise money at a time when billions of dollars of new bonds and loans are expected to hit the market, largely to fund the boom in merger activity.