NEW YORK -- Fitch may downgrade General Motors Acceptance Corp.’s ratings if there is no progress on a partial sale of the unit by the end of this quarter, according to a Reuters report.

The warning came a day after GM announced a new round of cost-cutting measures but failed to announce any decision on a sale of GMAC, sending bonds of GM and GMAC lower.

If there is no definitive agreement on a sale by the end of the first quarter, Fitch said its ratings would be reviewed and possibly downgraded. In addition, ratings on Residential Capital Corp., a holding company for GMAC's real estate financing businesses, may also be cut if there is no sale.

For now, GMAC's ratings remain on review with an "evolving" status, meaning they may be raised, lowered or affirmed.

A rating upgrade was a key reason for GM's decision to sell a controlling stake in GMAC, which needs access to low-cost funding so that it can finance GM's car sales. GMAC's borrowing costs in the unsecured bond market surged last year after its ratings were cut to junk along with GM's.

Fitch currently rates GMAC "BB," the second-highest junk rating, while Residential Capital is rated "BBB-minus," one step above junk status.