Preference shareholders in Wella, the German haircare company, have vowed to fight for a higher offer from Procter & Gamble after Clayton Daley, the US company's chief financial officer, said its €5.4bn ($6.2bn) takeover offer was final.

Stephen Aulsebrook, co-chairman of Close Brothers Corporate Finance, is advising a group comprising 34% of Wella's preference shareholders. These include Elliott Advisors, a US hedge fund reported to be considering suing BaFin, the German financial regulator, for not protecting Wella shareholders.