A second US ratings agency has downgraded General Motor’s (GM) debt rating to ‘junk’.

The downgrade by Fitch Ratings, follows Standard and Poor’s decision earlier this month and will mean that the group’s borrowing costs will increase, as well as limiting its options for raising funds.

Fitch’s decision will also push GM out of the Lehman Brothers Credit Index, which only quotes companies whose average rating is at ‘investment grade’.