Private equity firm Riverstone Holdings LLC has made a $200 million investment in Ridgebury Tankers LLC, a company that buys and operates tankers.

Riverstone’s investment came beside a $5.6 million commitment from Ridgebury’s management.

Ridgebury, based in Ridgefield, Conn., buys and operates Suezmax tankers that transport products for commodities companies, traders and government-owned entities.

Riverstone is an energy-focused private equity firm, based in New York, which has raised about $24 billion in equity through its seven investment funds. In Semtember the firm agreed to invest up to $200 million in Kerogen Energy Holdings LLC and in July agreed to invest up to $500 million in Meritage Midstream Services II.  

Energy industry