Three US private equity companies and Philippine conglomerate San Miguel Corp. are among 12 firms that have submitted letters of intent to bid for the government's majority stake in United Coconut Planters Bank, a person with knowledge of the matter said. CAP IV Engagement Limited, an affiliate of Carlyle Asia Partners IV, Lone Star Funds and TPG Capital Management LP, are interested, while Japan's Mitsubishi UFJ Financial Group Inc is the only foreign bank in the race, said one source, who was not authorized to speak to the media on the matter.