By Ian Walker

LONDON--Wm Morrisons Supermarkets PLC (MRW.LN) has returned to growth for the first time since December 2013, and is the only one of the top four grocers to record a rise in sales, according to a survey on Tuesday.

For the 12 weeks ended May 24, Wm Morrison's sales rose 0.1% to 2.78 billion pounds ($4.3 billion) and its market share remained steady at 10.9%. Wm Morrison is widely expected to fall from the FTSE100 index later this month in the quarterly review, based on indicative data from FTSE International. Its share price has fallen 15% over the past 12 months.

"A committed core of loyal Morrisons consumers is responding positively to recent initiatives and business has been boosted by online sales. Morrisons' performance is an improvement on what was a difficult May 2014, so this is only the first step in any future recovery," Fraser McKevitt head of retail and consumer insight at Kantar Worldpanel said.

Outside the top four, the only other grocers to increase market share and sales were up-market retailer Waitrose and German discounters Aldi and Lidl, according to Kantar, which monitors the household grocery purchasing habits of 25,000 demographically representative households in the U.K.

Waitrose sales rose 1.6% to GBP1.31 billion and its market share rose to 5.2%, from 5.1% in the 12 weeks ended May 25, 2014. The combined market share of Aldi and Lidl rose to 9.3% in the 12 weeks, compared with 8.4% in the year earlier period. Aldi sales have risen 16% to GBP1.38 billion, while Lidl's sales are up 8.8% to GBP982 million.

Number one retailer Tesco PLC (TSCO.LN)'s market share fell to 28.6% in the 12 weeks ended May 24, compared with 29% in the comparable period ended May 25, 2014, while Asda's share fell to 16.6%, from 17.1%. Tesco sales are down 1.3% over the period to GBP7.28 billion, while Asda's sales are 2.4% lower at GBP4.24 billion

J. Sainsbury PLC (SBRY.LN)'s market share was unchanged at 16.5% in the period, but sales have dipped 0.3% to GBP4.19 billion.

"All of the major supermarkets are finding growth difficult as prices have been declining since September 2014. Yet while like-for-like groceries are 1.9% cheaper than this time last year this is not as steep a fall as last month, when prices were down by 2.1%. This means that if current trends continue, prices will once again start rising by the end of the year," Mr. McKevitt said.

Write to Ian Walker at ian.walker@wsj.com

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