Aberdeen-based oil and gas logistics group Asco has been sold to a private equity firm in a deal said to be worth about £250m.
Asco operates worldwide and employs 1,600, with half based in Scotland.
It has been acquired by Doughty Hanson, one of the biggest private equity firms in Europe.
The firm said the deal gave it a foothold in a market which was "fast growing with significant, long-term growth potential".
Asco is currently owned by Phoenix Equity Partners and co-ordinates the supply of goods, from drilling equipment to food, destined for and returning from oil rigs and platforms.
It is also involved in specialist international logistics and oilfield waste management.
John Gemmell, principal at Doughty Hanson, said: "Asco is internationally recognised for its strong and reliable service capabilities and impeccable safety record.
"With growing demand for energy, the company is well positioned to benefit from the trend towards specialist outsourced logistics, particularly in the emerging high-growth oil and gas markets."
Billy Allan, chief executive of Asco, added: "Having Doughty Hanson behind us is fantastic news for the business and I'm looking forward to developing a strong partnership with them."