The Anglo-South African financial services group Investec has joined several international banks eyeing bids for the international arm of Coutts, the wealth management unit of RBS. At least half a dozen parties have expressed interest in buying Coutts International, which has been put up for sale by RBS. Coutts International is expected to change hands during the course of 2015, having been identified as non-core by Ross McEwan, RBS’ chief executive. It is unclear exactly how much the Coutts International business is worth, although analysts have speculated that it could fetch between £500 million and £650 million. A sale will not include a licence to use the famous wealth management brand, which will remain attached to Coutts’ UK operations. RBS is retaining the domestic franchise, which is among the world’s oldest private banks, with a heritage dating back to the late 17th century.