ADP Brokerage Services Group, a division of consulting firm ADP, is also to take over WestLB's foreign exchange and money market processing in the German bank's Dusseldorf and New York offices. The service will be run on the consultancy's Tradethru system.
Tradethru software automates the procedures involved in processing a trade, including portfolio and risk management.
West LB's London office said it had reduced its costs for foreign exchange and money market processing by 70% after signing a deal with ADP in 2002.
Daniel Mayo, lead analyst in the financial services practice at Datamonitor, said investment banks were putting in enterprise application integration and workflow software to cut costs by automating the trading process.
"The key thing for the software is to deal with things that go wrong during the trading process," he said. "Software that can automate much of this can save banks money."