Ulster Bank's parent company, Royal Bank of Scotland, has begun to unnerve investors with talk of another big potential deal.
Chief executive Mr Fred Goodwin helped set the rumour mill in motion early this month when he said, after announcing half-year results, the company might go to shareholders for funds if the right acquisition came along.
He also said Royal Bank would be interested in buying US retail bank Sovereign Bancorp if it was for sale. Sovereign Chairman Mr Jay Sidhu said last month his bank would be for sale at the right price, igniting speculation a deal for the US bank, now worth $5.44 billion, was in the offing.
Since Royal Bank's results day when it announced a 10 per cent rise in first-half pretax profit, its shares have fallen almost 9 per cent, making it the worst-performing bank stock in London's FTSE 100 index of blue chips.
That reflects investors' concerns that the British bank may issue new shares to pay for its next acquisition.