Tesco (TSCO) may have been the big four winner from the monthly grocery market share data this week, but it was a loser as far as the City was concerned.

Despite Tesco posting the best growth of the big four supermarket players over the 12 weeks to 19 May, according to Kantar’s market share data, the supermarket’s shares plunged 5.2% to 225.8p on Wednesday. Tesco was the only big four supermarket not to post a drop in sales over the period and has now posted the best growth of the mainstream mults for the fifth consecutive period.

However, investors were concerned about a notable slowdown in sales momentum towards the end of the period, which dragged its growth back from 1% in the previous monthly market share figures. Notably, Tesco’s most recent four-week sales were down 2.2% - a figure only surpassed by a 3.3% slowdown in sales at Sainsbury’s over the four-week period.

Bernstein slashed Tesco’s first quarter like-for-like growth expectations from 1.5% to just 0.3%, but the broker cautioned: “This is a significant drop, however we expect the tougher May comparatives coupled with the cooler May this year to be a drag on like-for-likes across UK retailers.”

Fellow grocery retailers were also caught up in the sell-off as grocery inflation fell to its lowest level since January 2017 at 1.2%, and poor May weather drove down overall grocery sales by 1.6% over the last four weeks, according to Nielsen.

Sainsbury’s (SBRY) shares dropped a more modest 0.2% to 198.4p despite again being the worst performing of the big four, as its underperformance is already priced into the shares. Morrisons (MRW) dropped 1.4% to 197.1p, Ocado (OCDO) fell 3.1% to 1,167.5p despite 6.4% 12-week sales growth and Marks & Spencer (MKS) was down 3.2% to 232p.

Elsewhere, reports this week suggested Premier Foods (PFD) is exploring the sale of its key Mr Kipling brand to bolster its balance sheet and cut debts.

Premier, which is currently conducting a strategic review exploring “options for increasing shareholder value” after two activist investors Oasis Management and Paulson joined the board in February, previously explored a sale of Ambrosia earlier this year but pulled the process due to insufficient demand.

Observers noted that Mr Kipling is one of Premier’s few remaining jewels in its largely low-growth portfolio and that a sale could signify a wider break-up of the group. Notably, on Thursday Premier said chairman Keith Hamill is to step down, having previously battled with Oasis and Paulson over the strategic direction of the company.

Premier’s shares continued to flatline, edging backwards from 36p to 35.8p over the week. The shares are down 9.5% year on year.