Twin Cities-based Supervalu is the parent company of Cub Foods and other grocery chains including Albertson's and Jewel-Osco. It's the third largest grocery company in the country but has not turned an annual profit in three years and its stock price is at an all-time low.

Supervalu's first quarter earnings were 45 percent lower than last year's. The company is being hurt by the lower prices competitors such as Wal Mart and Kroger are offering.

As Bloomberg noted, Supervalu's share price is down 35 percent so far this year. Now it's credit is also taking a hit. Reuters reports Standard & Poor's has put a negative watch on Supervalu.