The Royal Bank of Scotland-led consortium bidding for Dutch bank ABN Amro is facing some key IT decisions following its successful takeover, which was confirmed when 86% ABN Amro's shareholders backed the bid.

The consortium, including Abbey owner Santander as well as Fortis, will pay £48bn in total for the bank. Rival bidder Barclays last week fell out of the running.

But the acquirers may face some difficult IT challenges as they decide what to do with ABN Amro’s systems, and it has been suggested that the complex nature of the bid may complicate matters.

Under the plan, RBS will take ownership of ABN’s wholesale and corporate banking, its Asian operations and certain European banking operations, while Fortis will own ABN’s Dutch retail banking, its global private clients and asset management businesses. This leaves Santander with current Latin American operations and Antonveneta in Italy.

Several analysts have already suggested that RBS may attempt to pare down ABN’s systems into a simpler structure.

Santander, meanwhile, is currently occupied with new plans for a global integration project to migrate the various payments systems it uses around the world onto a single IT infrastructure.

A further possible complication could emerge with the decision over what to do with ABN’s £1.2bn multi-supplier outsourcing deal with Accenture, IBM, Infosys, Tata Consultancy Services and Patni, which it signed in 2005.

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