Analysts began speculating when John Stewart, the British boss of NAB, declined to rule out absolutely the sales of the banks.
This would be in addition to Northern Ireland’s Northern Bank and the Republic’s Bank of Ireland, which have been on the market for several months.
NAB has sought to integrate its four European banks in recent years by centralising the product development, marketing and other aspects of the business, making it easier for a new owner to integrate.
Hugh Maxwell-Davis, banking analyst for investment bank Morgan Stanley, said: “It is not inconceivable that interested bidders would view Clydesdale and Yorkshire banks as potentially available, given NAB’s apparent dwindling appetite for European exposure.”
Yulande Stratford, spokeswoman for NAB, said: “We don’t comment on market speculation. But we are looking for interested parties in relation to our subsidiaries Northern Bank and National Irish.”
Peter Brown, spokesman for Yorkshire Bank, said: “We never comment on what is pure media speculation. The stance taken by NAB regarding the Irish banks is well documented but can’t be compared to the status of the Yorkshire and the Clydesdale.”
Andy Frankish, technical director for Mortgage Talk, said: “From an intermediary perspective we have little dealings with either the Yorkshire or the Clydesdale. But if they are to be sold it may be a lift for the market if the buyers become proactive intermediary lenders.”