The Dutch Supreme Court announced Tuesday that it will issue a verdict on Dutch banking giant ABN Amro's sale of its American subsidiary LaSalle on Friday.

The British bank of Barclays and a consortium led by Royal Bank of Scotland (RBS) are both bidding for the takeover of ABN Amro, with the latter making the bid on condition that LaSalle is not sold. Whoever succeeds, the merger would be the biggest ever transaction in the financial sector.

ABN Amro agreed in March to sell LaSalle to Bank of America for 21 billion euros. ABN management has openly supported ABN's merger with Barclays, saying the consortium led by RBS will split ABN after takeover while Barclays will keep the bank's core interests intact.

ABN shareholders, many of whom see the consortium bid as more attractive than Barclays', are opposed to the sale and they took the matter to court.

A commercial court in Amsterdam decided in early May that the sale should not have taken place without permission from the shareholders. The transaction was therefore frozen.

In late June, Advocate General Vino Timmerman said in his recommendation to the Supreme Court that ABN did not need shareholder approval for the LaSalle sale. The Supreme Court follows such recommendations in 80 percent of cases.

If the Supreme Court overturns the commercial court ruling, Barclays' chances of a successful takeover of ABN would increase. The consortium, consisting of the RBS, Belgian-Dutch bank Fortis and Banco Santander from Spain, may be forced to make a bid for ABN without LaSalle.