Ford and General Motors' new union contracts may qualify them for higher credit ratings. Moody's Investors Service said it's reviewing its ratings for Ford.

The Dearborn, Mich., auto maker reached a deal on Tuesday with the United Auto Workers for a new four-year contract.

The automaker's ratings under review include "Ba2" for corporate family and probability of default, and "Ba3" for senior unsecured debt, both of which are so-called junk status.

They also include "Baa3" for secured bank debt, the lowest level of investment grade.

An upgrade would return Ford more squarely to investment-grade status, which the automaker has said is one of its top goals.

About $55 billion of debt would be affected.

Moody's is already reviewing Detroit-based General Motors' ratings after its workers ratified a similar contract last week.