The following commentary comes from an independent investor or market observer as part of TheStreet's guest contributor program, which is separate from the company's news coverage.NEW YORK ( Trefis) -- Both S&P and Moody's are reviewing Ford's ( F) credit ratings for possible upgrades, after a tentative agreement was struck between Ford and United Auto Workers (UAW). The agreement still needs to be ratified by unions and could face a tough time as some local unions have voted against it. With the proposed agreement, Ford will limit its fixed costs by paying its workers more in profit-sharing and signing bonus instead of pay increases. Currently, Ford is rated BB- by S&P and Ba2 by Moody's, and we believe that a rating upgrade to near investment grade levels is likely once UAW votes in favor of the agreement this week. A similar contract between GM ( GM) and UAW led Fitch and S&P to upgrade GM's credit ratings because of cost control benefits.