Carlyle and the European Bank for Reconstruction and Development (EBRD) agreed on 29 October 2026 to sell Black Sea Oil & Gas (BSOG), Romania's largest offshore natural gas producer, to Mazarine Energy B.V. for an undisclosed sum.
Why Mazarine Energy B.V. is buying Black Sea Oil & Gas S.A. and BSOG Holding Activity S.A. (BSOG)
Mazarine, founded in 2013 by chief executive Edward van Kersbergen, has operated in Romania since 2017 alongside its assets in Tunisia, and in 2026 entered the Dutch market by acquiring a 50% stake in Wintershall Noordzee B.V. BSOG will remain operator of the Midia Gas Development, and the company says it is pursuing further offshore gas development, offshore wind, carbon capture and storage, and biomethane plants through its subsidiary BSOG Energy.
Deal terms and financing
The parties did not disclose the price. The sale covers Black Sea Oil & Gas S.A. and BSOG Holding Activity S.A. Jefferies acted as financial adviser to Carlyle.
Regulatory approvals and timing
Completion is subject to customary regulatory approvals; no timetable was given.
Market context
Under Carlyle's ownership BSOG led more than US$400m of investment in the Midia Gas Development, comprising the Ana platform, a 126km subsea pipeline and the Vadu onshore gas treatment plant. Production began in June 2022 and has covered about 12% of Romania's domestic gas demand. Mazarine is itself a former Carlyle portfolio company.
