Some of the nation's biggest banks are in for a windfall - on top of the $700 billion government bailout - thanks to a new tax policy quietly issued by the Treasury Department. The notice gives big tax breaks to companies that acquire struggling banks hit hard by the mortgage crisis. In some cases, the tax breaks could exceed the cost of acquiring the banks, according to analyses by private tax experts. The change could cost the Treasury as much as $140 billion by enabling firms that acquire struggling banks to use more losses incurred by those banks to offset their own taxable profits. San Francisco's Wells Fargo & Co., which made a bid to acquire Wachovia Corp. just days after the notice was issued, stands to reap about $20 billion in additional tax savings because of the change, according to the analyses. Wells Fargo paid $14.8 billion in a stock deal to buy Wachovia. The notice was issued Sept. 30 as Congress debated the $700 billion bailout plan. Some members of Congress are upset that such a sweeping tax change was issued with no public hearings or congressional input. I am concerned that the notice, which was never debated by Congress, could end up costing taxpayers tens of billions of more dollars on top of the hundreds of billions of dollars already approved by Congress in the financial rescue plan," Sen. Chuck Schumer, D-N.Y., said in a letter last week to Treasury Secretary Henry Paulson. Some tax lawyers questioned the legality of the notice. Before the notice was issued, the merged bank could write off only a limited amount of the losses. The notice removed those restrictions, enabling the acquiring banks to make huge reductions in their tax liabilities.