The UK grocery market share of Tesco
Market research by Kantar WorldPanel said Tesco's market share fell 0.6 percent year on year to 29.7 percent in the 12 weeks to February 19.
In contrast, the completion of the conversion of Netto stores acquired last year helped Britain's No. 2 grocer Asda, owned by Wal-Mart Stores
Tesco issued its first profit warning in living memory on January 12.
No. 3 player J Sainsbury
Wm Morrison Supermarkets
Waitrose, owned by John Lewis
Kantar Worldpanel said overall grocery sales in Britain climbed 4.5 percent year on year in the latest 12-week period, against 4.2 percent in the 12 weeks to January 22.
While the growth rate remains lower than grocery price inflation, currently at 5.5 percent, the gap between the two measures is narrowing -- meaning pressure on household budgets, while still strong, is not getting any worse, said Kantar Worldpanel director Edward Garner.
Separately on Tuesday, a survey by the Confederation of British Industry said British retail sales improved more than expected in February.
(Reporting by James Davey; Editing by David Hulmes)