General Motors Co.’s outlook was revised to positive from stable by Standard & Poor’s Ratings Services, which also raised Ford Motor Co. to investment grade as Detroit automakers reap profits not seen since the turn of the century.

GM’s outlook is a sign the ratings company will probably boost the largest U.S. automaker to investment grade. S&P increased Ford to BBB-minus, the last major ratings company to rate the carmaker investment grade.

“The outlook revision reflects the potential for an upgrade by the end of 2014,” S&P said in a statement. “We will monitor GM’s ability to maintain market share and profitability in North America.”

GM’s corporate credit rating is BB-plus, the highest non-investment grade. The Detroit-based carmaker is introducing 18 new and refreshed vehicles this year in the U.S., transforming its lineup into one of the newest in the industry from the one of the oldest.

The new products along with the U.S. government’s announced plans to exit its ownership of GM after a 2009 rescue have given investors increased confidence in the automaker.

Fitch Ratings last week revised its outlook on GM to positive and said further improvements by the company could lead to an upgrade within the next 24 months. Fitch also rates GM as BB-plus.

GM along with Ford fell to junk status in 2005 as part of a slide that eventually included GM’s government-backed bankruptcy reorganization in 2009. Ford avoided bankruptcy and was returned to investment grade by Fitch Ratings and Moody’s Investors Service last year.