Former BlackRock fund manager Mark Lyttleton was arrested last month on suspicion of insider trading, according to reports.
Concerns raised by ratings agencies, analysts and hedge funds have pushed bank shares lower this morning as the FTSE 100 snaps seven straight days of gains.
M&G has lost its number one spot at the top of the widely followed Pridham report, after sales at rivals BlackRock and Standard Life surpassed the Prudential-owned asset manager.
Mervyn King, the outgoing governor of the Bank of England, has been tipped to give the Chancellor a helpful boost this week by upgrading growth prospects for the embattled UK economy.
London blue-chip index has crossed the threshold level of 6,600 for the first time since 2007 after a seven-day climb.
BT shares have rocketed this morning after the group reported forecasting-beating results which have left it ready to take on rival Sky with its broadcasting plans.
Japan's Nikkei 225 index has closed above 14,600, a fresh-five year high, as the yen dropped to a four-year low against the dollar.
The Bank of England has held interest rates for the 50th month in a row and opted not to increase the size of its QE programme at its May meeting.