Tesco, Britain's biggest retailer, rose its sales in the past 12 weeks by increasing its sector dominance in the Christmas period, according to data.
Tesco's market share increased by 0.2 percentage points, to 26,6% in 12 weeks to Nov. 6.
A rise of 3.1% amongst smaller rivals Sainsbury's (SBRY.L) and Asda saw sales fall 2.4% and 4.7%, and all lost market share.
NielsenIQ's data echos data from rival researcher Kantar last week.
Tesco reported a 166% jump in first half profit last month and raised its full-year earnings forecast despite supply chain disruption. read more about the facts, and read more about this.
NielsenIQ said total grocery sales in the four weeks from the 1st to Nov. risen 2.0% in the last four weeks, versus high comparative figures ahead of the second national coVID-19 lockdown last year.
Sales have risen, however, 4.9% over the same period in 2019, up from 49% on the same date in 2019.
The researcher noticed that compared to last year, in-store visits to supermarkets increased 6,5%, totaling 28, million more visits.
In contrast, the sales on the internet fell to 12.2 %, down from 12.6 in the four weeks preceding.
(1 = 0.7443 pounds)