So much, it might seem, for the thaw between US and European Union trust-busters. Christine Varney, President Barack Obama’s choice as the US justice department’s antitrust chief, has pledged to reassert the government’s role in policing anticompetitive behaviour after the laisser-faire Bush years. That should chime with the European Union’s more interventionist approach. Yet the European Commission last week extended its investigation of Oracle’s planned $7.4bn merger with Sun Microsystems into a second stage of up to four months – after Washington cleared it without conditions. Cue alarm bells all round. This is the first big all-US merger the EU has examined during the Obama presidency; if blocked, it would be the first US deal to suffer that fate since General Electric-Honeywell in 2001.

But hold on. Brussels has not blocked the deal, nor even concluded yet that there is a competition issue. It does, however, want more time to examine whether there might be, in one area: that the deal could thwart the growth of MySQL, a popular, open-source, corporate database programme owned by Sun that competes with Oracle’s proprietary software. Oracle says since MySQL is open-source, by definition there are no obstacles to competitors developing commercial products based on it; rivals have complained to Brussels that there are. The Commission, unlike the US regulator, is legally obliged to probe any potential competition problem, otherwise it can be challenged in the European Court.