The European Commission will formally propose new merger rules tomorrow that will begin the debate among the 15 European Union members over regulating company acquisitions.
The Commission is pushing the review because the European Union's court of first instance this year reversed three of the Commission's prohibitions. The court said the Commission was sloppy and failed to prove its case.
Competition Commissioner Mr Mario Monti's proposals will mark the end of months of drafting, consulting and revising, but the final decision on merger rules will be up to the EU's 15 member states.
Mr Monti did much the same thing for a major overhaul of antitrust rules and it took member states nearly a year to settle differences before approving a final version this month.
Companies want the rules updated because they believe they often do not get a fair deal before the Commission and do not like the way they are reviewed.
One innovation is to improve the quality of the Commission's work by installing a chief economist, consulting with a review committee and seeking closer oversight from a member nation advisory committee.
But member states find some of the Commission's proposals difficult or unworkable.
For example, Brussels reviews the biggest cases while member state competition agencies review smaller cases. There has always been a question of where to draw the line between big and small.
Mr Monti proposed that mergers that need review in three or more countries should wind up in Brussels to make life easier for companies.
But Germany and some others raised objections, so Mr Monti came up with a more complicated approach that some countries' competition officials find difficult to understand.