A High Court challenge has been launched against plans by Permanent TSB to raise €400m through a share placing to institutional investors ahead of listings on the London and Dublin stock exchanges.

Permanent TSB Group Holdings Plc may raise as much as €400m in a share sale, according to a person with knowledge of the matter, more than double the amount signalled by the lender last month.

Shareholders of Permanent TSB who wish to challenge the constitutionality of laws under which the State has recapitalised the institution with €4bn cannot do so by amending their existing court proceedings, the High Court has ruled.

Irish Life Group Ltd chief Kevin Murphy postponed his plans to retire at the end of 2012 as the Government revived talks to sell the state-owned insurer to Canada’s Great-West Lifeco Inc.