* EU Commission must approve the planned merger
* Deal would create Europe's dominant bourse
* LSE plans to sell LCH SA making good progress (Adds detail, bullet points)
FRANKFURT, Dec 14 (Reuters) - The European Commission continues to have concerns about the planned merger of Deutsche Boerse and London Stock Exchange Group (LSE), but to a lesser extent than three months ago, the stock market operators said in a joint statement on Wednesday.
The groups said they had received a so-called statement of objections from the Commission that outlined fewer worries over the tie-up compared with a first letter sent at the end of September.
"The list of concerns has shortened," a Deutsche Boerse spokeswoman said. "We will examine the document in the coming days and continue our constructive dialogue with the EU Commission."
The Commission, the EU's executive, must approve the merger, which would create Europe's dominant bourse.
The companies also said that plans by LSE to sell its LCH SA -- the French clearing subsidiary of its LCH.Clearnet group -- was making good progress. The plans were first announced on Sept. 28.
Sources told Reuters this week that European Union competition regulators had whittled down their concerns about the proposed merger of Deutsche Boerse and LSE to focus mainly on the clearing of derivatives contracts.
Clearing has become a major issue because, following global reforms introduced after the 2007-09 financial crisis, banks must clear the bulk of their derivatives trades to make them safer and more transparent. (Reporting by Andreas Kroener; Writing by Christoph Steitz; Editing by Maria Sheahan and David Goodman)