FOR the chief executives of Deutsche Börse (DB) and NYSE Euronext, this week’s hobnobbing in Davos was strictly business. A $9.5 billion plan to unite the two exchanges was derailed in early December when European Commission staff revealed they were likely to advise blocking it on competition grounds. The exchanges are lobbying hard to persuade the 27 EU commissioners to ignore their staff and approve the deal. A decision is due to be made on February 1st.On the face of it, investors should support the commission’s recommendation to stymie the deal. Its competition wing is mandated to stop mergers that are likely to raise prices, reduce quality or dull innovation. In this case the concern is that the exchanges’ derivatives businesses—DB’s Eurex and NYSE Euronext’s Liffe—would share over 95% of European trading for some assets. There may also be concerns that a merged exchange would be able to force investors to use its clearing facilities (for which it could ratchet up charges) once trades have been made.But there are reasons to think that the deal could be beneficial to investors. Exchanges are platforms on which buyers and sellers can meet, so a lower number of exchanges, which increases the potential for buyer-seller matches, can be better than a fragmented system. In addition, making all trades on one exchange could lower investors’ costs. This is because some assets (…

Original post by The Economist: Business