Citigroup's (C) Citi Investor Services said Thursday that it has won a full middle office mandate from Aegon's (AEG) unit Aegon Asset Management covering $380 billion in assets under management.

The company said the mandate adds investment book of record, trade management, settlement and performance measurement services to its existing custody, depositary, collateral, fund accounting, administration and transfer agency services for Aegon Asset Management.

As part of the transition, Aegon Asset Management's operations employees in Budapest, Hungary, have joined Citi Investor Services to support the expanded services on BlackRock's Aladdin investment platform, it added.