Standard & Poor's has flipped its outlook on Alcoa (AA) from "stable" to "negative," while maintaining its credit rating of BBB- on the aluminum producer. In the press release announcing the move, S&P expressed concern about the current market for the company's products. "Our outlook revision reflects our view that low aluminum prices will constrain 2013 operating performance and credit measures," the rating agency quoted its analyst Marie Shmaruk as saying.

S&P expects that those prices will increase in the near future, to over $0.90 per pound in 2014, from the current level of roughly $0.85.