June 26 (Bloomberg) -- Barclays Plc won the support of a Dutch Supreme Court adviser in its $85 billion battle with Royal Bank of Scotland Group Plc to acquire ABN Amro Holding NV, the country's biggest bank.

The Advocate General, whose rulings are followed about 80 percent of the time by the high court, said ABN Amro doesn't need permission from shareholders to sell Chicago-based LaSalle to Bank of America Corp. London-based Barclays has tied its 63 billion-euro ($85 billion) bid for ABN Amro to a separate sale of LaSalle.

The advisory opinion is a setback for a group led by Edinburgh-based Royal Bank, which wants to buy LaSalle as part of a 71.2 billion-euro takeover of Amsterdam-based ABN Amro. The acquisition would be the country's first by a non-Dutch bank and the largest in the financial-services industry, topping Travelers Group Inc.'s $69.9 billion buyout of Citicorp.

``It's a surprise ruling, and it looks like bad news for Royal Bank,'' said Colin Morton, who helps manage $1.8 billion at Rensburg Sheppards Plc in Leeds, England, including Royal Bank and Barclays stock. ``The concerns are that the deal will get caught up in the courts or that someone will end up paying too much to win the day.''

Shares of Barclays, run by Chief Executive Officer John Varley, declined 1.3 percent to 710.5 pence in London. Royal Bank's stock rose 0.2 percent to 641 pence. Shares of ABN Amro declined 0.1 percent to 34.41 euros in Amsterdam.

`80 Percent'

The Hague-based Supreme Court said today it intends to make a final ruling before mid-July. ``In 80 percent of the cases, the high court has ruled in accordance with the advice of the Advocate General,'' said Arnoud Boot, a professor of economics at the University of Amsterdam.

Should the Supreme Court follow the advice posted today, it will overturn a decision by the Enterprise Chamber of the Amsterdam Court of Appeal on May 3 that froze ABN Amro's sale of LaSalle. Bank of America, ABN Amro and Barclays appealed.

``We are pleased that the Advocate General has recommended the Enterprise Chamber's decision be reversed and that the injunction against completing our transaction be lifted,'' Bank of America spokesman Robert Stickler said in an interview today. ``We look forward to the Supreme Court's decision.''

`Walk Away'

Royal Bank's bid for ABN Amro reflects its goal of reducing its dependence on the U.K., where it earns most of its revenue, by adding branches in India, China and the U.S. Its partners in the bid are Spain's Banco Santander SA and the Brussels- and Utrecht-based bank and insurer Fortis.

``The consortium may now walk away,'' said Guy de Blonay, a London-based fund manager at New Star Asset Management Group Plc. De Blonay holds Barclays, Royal Bank, ABN Amro and Santander stock and helps manage about $41 billion. ``Assuming the court follows the advice of the advocate general, we will know within the next two weeks if the consortium is going to withdraw or offer an ex-LaSalle deal,'' said de Blonay.

The Dutch shareholder group VEB filed a motion in April with the Enterprise Chamber to freeze the sale of LaSalle to Bank of America. VEB today vowed to ``use every possible method to block the LaSalle sale.''

The investor group will consider filing a new appeal to the Enterprise Chamber should the Supreme Court decide to overturn the May 3 decision, Director Peter Paul de Vries told reporters at a press conference in The Hague.

``This advice clearly is negative for ABN Amro shareholders, as it seems that reasonable shareholder rights are denied,'' Thijs Berkelder, an Amsterdam-based analyst for Petercam, said in a note today. The Royal Bank-led group ``will have to rethink its chances of a new offer, one for ABN Amro excluding LaSalle,'' said Berkelder, who has a ``reduce'' rating on ABN Amro shares.

Obligation to Shareholders

The court adviser, Levinus Timmerman, didn't deal with VEB's question of whether ABN Amro had any legal obligation to shareholders to consider the interest of the Royal Bank group before selling LaSalle to Bank of America. He merely concluded that Dutch corporate law didn't require a shareholder vote on the LaSalle sale.

``The Advocate General only concludes that, under Dutch company law, the transaction does not require the approval'' by a general meeting of shareholders, according to the decision.

Timmerman, 57, has written several books on Dutch corporate law. He was a university professor in Groningen and Leiden, where he wrote on the university Web site that he wants to contribute to a Dutch corporate law system that is ``competitive in a fast changing world economy.'' Timmerman, who has been Advocate General since 2003, is a professor at Rotterdam, according to the Supreme Court Web site.

`Tennis Match'

The Supreme Court may not directly follow the Advocate General's advice, Gert Jochems, director of Amsterdam-based Financial Markets Conduct, said in an interview today. ``In the Netherlands, court ruling is about the spirit of the law and not about the exact wording,'' Jochems said.

TCI Fund Management LLP, a London-based hedge fund, helped put ABN Amro in play in February by urging the bank to consider a breakup. Spokesman Paul Kaju declined to comment today.

Royal Bank CEO Fred Goodwin is seeking LaSalle to help compete with larger rivals in the U.S., where Royal Bank generates about a quarter of pretax profit. Goodwin will also hold onto ABN Amro's Asian operations and its corporate banking business.

``It's a tennis match, and right now it's advantage Barclays,'' said Mamoun Tazi, an analyst at Man Securities Ltd. in London who has a ``neutral'' rating on Barclays and Royal Bank stock. Barclays shares fell because investors think it is more likely the U.K.'s third-largest bank will prevail, he said.

ABN Amro said in a statement it will ``study the advisory opinion and await the judgement of the Supreme Court.'' Barclays spokesman Robin Tozer said the bank will look at the opinion with interest. Royal Bank spokeswoman Carolyn McAdam and spokespeople for Banco Santander and Fortis said they are examining the recommendation and declined to comment further.

To contact the reporter on this story: Martijn van der Starre in Amsterdam vanderstarre@bloomberg.net

Last Updated: June 26, 2007 13:43 EDT