There's been a blow to a $US7 billion takeover of Sun Microsystems by the business software company Oracle.
The European Union competition comission has launched a probe of the deal on concerns a tie-up could dent competition in the database
The deal was approved by shareholders in July and the United States Department of Justice.
The BBC reports the takeover has already been held up over questions about licensing Java. The deal was expected to be finalised at the end of the (northern) summer.
Shares in both companies have fallen: investors fear a regulatory delay could allow rivals such as Hewlett-Packard and IBM more time to poach hardware customers. IBM earlier abandoned an attempt to buy Sun earlier this year.
A decision is due by 19 January.