Punjab National Bank (BSE:532461) has appointed merchant bankers to sell a controlling stake in PNB Housing Finance Limited (BSE:540173), a top bank official has said. The deal is expected to be finalised in the next few months, the official added. Last week, the bank and The Carlyle Group L.P. (NasdaqGS:CG), which owns over 32% in PNB Housing Finance, had announced their plans to sell at least 51% stake in the company.