Another quarter of like-for-like sales growth pushed Sainsbury’s shares up a fraction this week, but the headline-grabbing food retail stock was Ocado.

Against a falling FTSE, Ocado shares rocketed 18% in three days to 324.8p on Wednesday and are now 61% up on their 201.9p value on 16 May - the day before its tie-up with Morrisons was announced. Its shares have soared not just because investors have been piling into the stock but also because short-sellers have closed their positions to minimise losses.

The percentage of Ocado’s stock out on loan to short-sellers has halved to under 8% from almost 15% in December. The hedge funds Blue Ridge Capital, Dalton Strategic Partnership and Kynikos Associates have all wound down their bets against the online grocer in the past fortnight.

Sainsbury’s shares climbed far more steadily this week - edging up 1% to 365p on Wednesday after the supermarket reported a 0.8% increase in first-quarter like-for-like sales.

Its trading update was in line with expectations but some analysts warned that growth could be harder to come by. “We believe it is clear that driving like-for-like growth in UK food is going to remain very difficult, particularly as comparisons toughen into the second quarter,” said Espirito analyst Robert Evans.

Meanwhile, there was plenty of news in soft drinks to swallow this week. On Tuesday, the Competition Commission gave a provisional green light to the proposed tie-up between AG Barr and Britvic. Both companies welcomed the news, but Britvic indicated its enthusiasm for a deal had waned. “Britvic highlights it is in a “different place” to last summer, which, in our view, probably reduces the likelihood of a deal this time round,” said Investec analyst Nicola Mallard.

Britvic shares dropped 3% to 486.5p and AG Barr shares fell 1% to 503p, reflecting investor fear a deal was now less likely to happen.

On the same day, Coca-Cola Enterprises issued a profit warning citing the “unexpectedly persistent” weak economy, poor weather, tax hikes in France and the competitive market in the UK. It said these factors had “dampened second quarter expectations”. Its shares dropped 3% to $35.90 in trading on the New York Stock Exchange.