ABN Amro on Tuesday scrapped its $12 billion bid for Belgium's largest bank, citing opposition from the target's board and an unfavorable regulatory environment.

The Dutch banking company, which launched its bid for Generale de Banque on May 26, retreated after being dealt a series of setbacks by both the target and by rival bidder Fortis Group.

On Friday, Fortis, a Belgian-Dutch insurance concern, sweetened its bid to $14 billion, a $3 billion increase.

On Saturday, Generale de Banque triggered a poison pill that would have made it difficult for Amro to take control, and a majority of its board declared that they considered Amro's bid hostile.

In a statement Tuesday, Amro said it withdrew its bid after concluding that Fortis had gained a decisive edge.

"ABN Amro is of the opinion that the arguments put forward by the board of directors of Generale Bank are unsound; it still considers its bid as friendly," the company said.

Amro also criticized the Belgian Banking and Finance Commission for failing to clarify the ground rules for the competing bidders.

The takeover battle was in its eighth day last Wednesday when the commission ruled that it would permit both bids to proceed.

Amro, Holland's largest banking company, has $114 billion in U.S. banking assets.

Subscribe Now

Access to authoritative analysis and perspective and our data-driven report series.

14-Day Free Trial

No credit card required. Complete access to articles, breaking news and industry data.