The Commission was notified about the deal on July 30, and it will now be looked at under the European Union Merger Regulation. It has an initial period of 25 working days to decide if it can clear the deal or if it needs to open a 90-day in-depth investigation, said a EU spokeswoman.
Oracle announced in April that it planned to acquire Sun for about $7.4bn in cash, or $9.50 per share. The acquisition would reshape Oracle, turning it into a hardware and software vendor that can compete more intensely with IBM and HP.
But it hasn't exactly been smooth sailing so far. The US Department of Justice extended its review of the deal on June 26 over concerns about the way rights to Java are licensed. Java is a software platform developed by Sun that can be used to develop and run applications on a wide variety of devices.
But at least one hurdle is out of the way. Sun shareholders voted on July 16 to approve the company's acquisition by Oracle, but not by a wide margin. Shareholders holding about 62 percent of Sun's stock voted in favor of the deal at a special meeting at Sun's offices in Santa Clara, the company said at the time.
The European Commission, which is the EU's executive and regulatory branch, has closely scrutinised US technology companies this year.
It found Intel guilty of antitrust abuse in May and fined the company just over €1bn, the largest single antitrust fine it has ever meted out to a company.