Standard & Poor's Ratings Services said Wednesday it was considering slashing the credit rating of big box electronics retailer Best Buy Co. Inc. (NYSE: BBY) to junk status, or non-investment grade.

The agency said the business model of the Richfield, Minn., company, which plans to shutter 50 big stores and replace them with 100 smaller ones to cut $800 million in costs over five years, is not working and that steps taken to date have not been enough to improve performance.

S&P, therefore, placed the company's BBB- corporate credit rating on CreditWatch with negative implications. If Best Buy's current rating is cut just one level, it will no longer have an investment-grade corporate credit rating, which will increase its borrowing costs.

We believe the restructuring of operations underscores the problems that Best Buy is having with its current business model, said S&P's credit analyst Jayne Ross.

S&P said it gauged the company's business risk profile as satisfactory and its financial risk profile as moderate.

On March 29, Best Buy reported a loss for its fiscal 2012 fourth quarter, which ended March 3, and the full fiscal year. The loss came despite a slight gain in revenue in the quarter.

Best Buy (NYSE: BBY) shares fell 64 cents, or 2.6 percent, to $22.91 in afternoon trading. That's near the stock's 52-week low of $21.79.