NYSE Euronext has joined Dutch and British financial authorities in examining trading patterns in ABN Amro 's shares and American depository receipts in the period before the multibillion euro (dollar) bidding war over ABN became public, the bank said Tuesday.

Separately, the Dutch Supreme Court said it has set Friday as the date for a key ruling in the fight between Barclays and a consortium of banks led by Royal Bank of Scotland to buy ABN Amro .