Bayer needs regulatory approval to take over Monsanto.

The European Commission announced Tuesday that it has begun its review of Bayer's $66 billion takeover of U.S. seed manufacturer Monsanto Co. (MON) .

"The Commission has preliminary concerns that the proposed acquisition could reduce competition in a number of different markets resulting in higher prices, lower quality, less choice and less innovation," the European Commission said in a statement. 

The European Commission has competition concerns if the two companies are allowed to merge, but there will likely be a series of divestitures in order to obtain regulatory approval. 

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