Shares in payment processor Worldpay jumped 9% in early trade after a report suggested it could be a bid target.
Wall Street Wires cited unnamed City sources as suggesting Worldpay had been approached by suitors.
The move in Worldpay shares also comes a day after Danish card payment services company Nets confirmed it had received takeover approaches.
Despite the jump in Worldpay shares, the FTSE 100 index was down 31.25 points at 7,345.84.
Shares in Sainsbury’s were flat after its latest sales figures came in slightly ahead of expectations.
The UK’s second largest supermarket chain – which also owns Argos – said like-for-like sales excluding petrol rose 2.3% in the 16 weeks to 1 July.
Outside the FTSE 100 index, shares in Imagination Technologies rose 8% after the company – which is up for sale and in dispute with Apple, its largest customer – said it had returned to profit.
The company reported a £2.4m pre-tax profit for 12 months to 30 April, compared with a £29.4m loss in the previous year. Revenues rose 19% to £145.2m.
On the currency markets, the pound edged up 0.1% against the dollar to $1.2948 and was also slightly higher against the euro at 1.1390 euros.