The 34.7 per cent stake is worth about $504m, and the management service agreement signed as part of the deal will give CBQ chief executive Andrew Stevens and director Omar al-Fardan seats in the UAB board.

CBQ bought 14.7 per cent of UAB on 13 December after commencing talks about an acquisition in the summer, and said it plans to build its stake to build its stake to 40 per cent.

CBQ pursued a similar strategy when it acquired a 34 per cent stake in National Bank of Oman in 2005. Stevens says CBQ will continue with this strategy of acquiring stakes in banks operating in other markets and signing management agreements with them to help expand its geographic base.