Police in London have arrested a man on suspicion of fraud in connection with huge losses at the Swiss bank UBS.
The bank said it had discovered unauthorised dealings which at first glance amounted to around 1.5 billion euros.
UBS made a brief statement shortly before the trading floors opened, sending its shares plunging eight per cent at one point in a market that was otherwise generally stable.
The bank said the rogue trading might lead to a loss in the third quarter of the year but added that clients are unaffected.
UBS have been struggling to rebuild customer confidence after being bailed out by the Swiss government in 2008.
The case echoes that of the French bank Société Générale, whose trader Jérôme Kerviel’s dodgy dealings lost the bank 4.9 billion euros in 2008, and landed him with a five year jail term.