About 5.5 million shares of the company traded in one block deal at a price of 0.408 lei each, Bucharest Stock Exchange data indicated.
The parties to the deal were not disclosed.
In regular trading, blue chip OMV Petrom was trading down 0.97% at 0.407 lei by 1111 GMT on the Bucharest bourse.
(1 euro = 4.5034 Romanian lei)