Allen & Overy is advising The Bank of Tokyo-Mitsubishi UFJ Ltd. (BTMU) on its proposed $5.75 billion acquisition of a majority stake in Bank of Ayudhya Plc., Thailand's fifth-largest bank.

BTMU plans to purchase as much as 75 percent of the available shares in Bank of Ayudhya, which includes a 25.3 percent stake presently held by GE Capital International Holdings Corp. GE has already agreed to sell its holdings to BTMU.

Thai conglomerate Ratanarak Group controls the remaining 25 percent share of Bank of Ayudhya, and has no plans to sell. Instead it will partner with BTMU to run the bank, according to a statement by BTMU.