AMSTERDAM, Netherlands (AP) — Bank of America Corp. and Barclays PLC both filed appeals to the Dutch Supreme Court yesterday over a ruling that froze the US-based company's $21 billion purchase of LaSalle Bank Corp. from ABN Amro.Control of Chicago-based LaSalle has become the key battle in the larger fight to acquire ABN Amro in what would be the largest takeover ever in the financial industry.

ABN is weighing two informal bids, a friendly all-share offer from Barclays worth around $84.4 billion and a hostile one, mostly cash, from a three-bank consortium led by Royal Bank of Scotland PLC worth about $94.7 billion.

The Barclays offer is dependent on the LaSalle sale going through, while the RBS bid is contingent on it being halted, since RBS also wants LaSalle.

"We're confident that the Dutch Supreme Court, when presented with all the facts, will overturn the (Amsterdam Superior Court's) decision," BofA spokesman Scott Silvestri said.

"I can confirm that we are filing legal documents as part of the appeals process," Barclays spokesman Robin Tozer said.

ABN Amro spokesman Piers Townsend confirmed his company would also appeal the ruling.

Supreme Court spokeswoman Evelien Hartogs said that ABN was expected to file an appeal today. "Each has their own standpoint," she said.

The Superior Court had found that ABN's boards had "misunderstood" their duties when they agreed to the sale of LaSalle without seeking shareholder approval, and because they tied it to the Barclays deal — effectively limiting their own shareholders' range of options.

Hans de Savornin Lohman, a lawyer for Loyens & Loeff who filed the appeal on behalf of BofA, told Dow Jones Newswires he expects a ruling in the first week of July.

According to the BofA appeal, US law should govern the sale of LaSalle, not Dutch law, since the sale contract was drafted in the US.