UK grocery retailer Wm Morrison faces a major challenge to restore sales at its new acquisition Safeway as the latest industry data revealed sales at Safeway stores continued to slide.

According to figures from market research firm TNS, Safeway’s market share in the 12 weeks to 23 May fell to 8.0%, compared to 9.1% in the year-ago period and 8.2% in the 12 weeks to 25 April.

However, the Morrisons chain maintained its market share of 6.2% from a month earlier, up from 5.7% in the year-ago period, reported Reuters.

Tesco continued to notch up market share to 27.6% in the latest period, compared to 27.5% a month earlier and 26.4% in the year-ago period. Asda’s market share of 16.6% was unchanged from a month earlier, while Sainsbury’s held onto its market share of 15.5% from a month earlier.