Brussels, Belgium ? European Union antitrust officials won backing Monday for their proposed fine against Microsoft Corp., the last hurdle before adopting a decision that could force far-reaching changes on how the U.S. software giant sells Windows.

Representatives from the 15 EU governments met for less than an hour behind closed doors to review the proposal from EU Competition Commissioner Mario Monti. A source familiar with the case, speaking on condition of anonymity, told The Associated Press they agreed to a fine but declined to elaborate.

Another source told Dow Jones Newswires the fine would be $611 million.

That would be a record for the EU in an antitrust case but far below the maximum $3.5 billion in Microsoft’s case and easily absorbed by a company with cash reserves in excess of $50 billion.

Other sources, also speaking on condition of anonymity, had estimated the fine would run into the hundreds of millions of dollars when the European Commission, the EU’s executive body, issues its ruling Wednesday.

EU rules allow the commission to fine antitrust violators as much as 10 percent of annual global revenue, although in practice they have been far lower. The largest imposed was less than 2 percent — $568 million — against Roche Holding AG, one of several companies caught fixing the prices of bulk vitamins in 2001.

The record penalty for charges similar to those Microsoft faces — abusing a monopoly position — is $92 million imposed on Swedish packaging giant Tetra Pak AB in 1991.

Analysts say even the maximum fine would be easily absorbed by Microsoft, which expects to generate nearly $36 billion in revenue this fiscal year and is sitting on cash reserves of more than $50 billion.

Monday’s meeting came a week after the same advisory panel unanimously backed Monti’s draft ruling, which sources familiar with the 5-year-old case say finds Microsoft abused its Windows monopoly, harming consumers and competitors in the markets for digital media and server software.