FL Group, the Icelandic investor that last month dropped out of the bidding contest for UK sandwich shop chain Pret a Manger, has suffered a Ikr27.1bn (€308m) writedown after its portfolio was hit by the turmoil in the global credit markets.

FL Group, which owns stakes in companies ranging from Commerzbank to UK retailer House of Fraser, blamed "exceptional turbulence" in the financial markets for forcing it to mark down the value of its investments.