Despite a court decision contradicting its interests, a consortium of buyers sweetened its bid for Dutch banking behemoth ABN AMRO (NYSE:ABN).

Royal Bank of Scotland is leading a group of financial interests that includes Spanish bank Banco Santander (NYSE:STD) and another Dutch banking and insurance interest, Fortis. Together, they've offered $98 billion for ABN, roughly a 10% higher premium than that offered by rival Barclays (NYSE:BCS). Instead of making a higher offer, the RBS-led group has instead increased the amount of cash in the deal, from 79% to 93%.

The consortium had hoped to also land ABN's LaSalle unit in the deal, but a court ruled on Friday that ABN AMRO was allowed to sell the unit to Bank of America (NYSE:BAC). ABN had made the sale as part of the offer from Barclay's, and had done so without shareholder approval. It was thought that selling off LaSalle would jeopardize the RBS bid, and shareholders were trying to thwart the transaction, since the consortium's bid was higher.

The LaSalle unit was seen as a plum prize for the group, one that would have been immediately accruable to earnings. Santander, for example, had hoped to get the unit's Latin American assets, which were considered particularly fertile for growth. As it stands now, the group would receive the cash realized from the LaSalle sale if its bid proves to be the winning one. Even so, ABN minus LaSalle is still expected to increase earnings for the consortium by 7% by 2010.

With the court ruling made, though, and Royal Bank of Scotland still interested, that leaves it up to Barclay's to consider raising its bid, an all-share offer worth about $91 billion. Analysts believe that it may not make a move; Barclays isn't tipping its hand. Without much geographic overlap between the two institutions, Barclays would be hard-pressed to come up with cost savings, though the LaSalle sale would allow it to return that cash to shareholders.

That doesn't mean it will be a loser, regardless of how the bidding turns out. Barclay's 20 largest shareholders -- comprising about 35% of its ownership interests -- also hold a significant stake in Royal Bank of Scotland. According to Reuters, they collectively own approximately 23% of that financial institution.

In any case, whichever bid ultimately wins out, the deal will be the largest banking merger ever, surpassing even the $57 billion deal that created Bank of America.

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Fool contributor Rich Duprey does not have a financial position in any of the stocks mentioned in this article. You can see his holdings here. The Motley Fool has a disclosure policy.