Investors in Prudential have been offered unprecedentedly high fees to sub underwrite the UK insurer’s £14.5bn (€16.9bn) rights issue, as chief executive Tidjane Thiam seeks to convince the group’s wavering shareholder base to support the takeover of AIA Group.

Institutional shareholders will be paid 2%, or £290m, to sub underwrite the deal, markedly higher than the standard 1.5 - 1.75% on offer for UK rights issues, according to a banker who had read the deal prospectus. Banks, led by Credit Suisse, HSBC and JP Morgan Cazenove, will share the remaining 0.75%, which equates to around £108m and a far cry from what they had in mind when the deal was first proposed.