ASDA raised its profits by 4% last year amid uncertain economic conditions and increased market share helped by the acquisition of Netto Foodstores.

Accounts filed at Companies House by the supermarket giant show the company made £767.8m profit before tax in 2011, compared with £739.1m in the preceding year.

Owned by America's Wal-Mart, Asda said revenues increased by 6.3% annually to £21.8bn due to underlying sales growth, store openings and the £752m acquisition of Netto in April last year.

The acquisition gave rise to £416m in additional revenue. The company said the stores acquired have been converted successfully into Asda operations.

Asda also opened 22 new stores during the year.

It said: "We strengthened our price leadership by enhancing the Asda price guarantee in the year, assuring customers that Asda will be 10% cheaper than its competitors."

In January Kantar Worldpanel, the retail markets specialist, said: "We continue to see a price war as the big four battle for market share.

"Tesco's Big Price Drop has had an aggressive response from its competitors and put pressure on its share, which has slipped from 30.5% a year ago to 30.1%.

"In contrast, Asda has seen a strong year-on-year performance, with its share up from 16.8% to 17.2%. This is in part thanks to the conversion of Netto stores which it acquired earlier in the year."