The second-largest US grocery supplies distributor, Supervalu, has reported that its quarterly earnings will fall below Wall Street forecasts.

Supervalu, which operates more than 1,300 retail stores, said the revised forecast was due to a sluggish economy and a deflation in some food categories.

The company said it expects earnings for the third quarter, ended 30 November, of 42 cents to 44 cents per share, compared with 43 cents a year earlier. Analysts on average expect 50 cents per share, according to research firm Thomson First Call.

Supervalu has forecast fourth-quarter earnings per share of 55 cents to 60 cents, against 51 cents a year earlier. Analysts’ average forecast is 60 cents, according to First Call, reported Reuters.

Two other US grocers, Safeway and Albertson’s have also recently warned on profit outlooks, as competition from discount giant Wal-Mart continues to take its toll.

Supervalu is due to release its third-quarter results on 18 December.