Investcorp, the global asset manager based in Bahrain, said Tuesday it had agreed to buy British oil services company Moody International for US$311 million, which includes an undisclosed level of debt.

"The acquisition of Moody represents an attractive investment opportunity for Investcorp given its leading niche positions, earnings generated worldwide from a very high quality client base, and the continuing strong growth in demand for services in the oil and gas sectors," Steven Puccinelli, head of Investcorp's European private equity team, said in a statement.

Moody's client base includes energy giants BP, Royal Dutch Shell, Statoil, Exxon Mobil, Chevron, Dow Chemicals, Saudi Aramco, Lukoil and Rosneft.

Investcorp is buying Moody from Close Brothers, the British investment bank and asset manager. Investcorp said it expected to complete the deal by the end of January.