It’s rare for a company to gain a land concession from the government and not have a conflict with the locals.
The ambassadors—to Cuba, the Philippines and Russia—will take their posts in July.
Phnom Penh Governor Kep Chuktema said he had not found bribery among any of the city’s eight district governors.
The visit comes follows an announcement last week that Cambodia will expand consular services to six cities in China.
All three companies are owned by Ly Yong Phat, a powerful senator for the ruling Cambodian People’s Party.
The 10-nation bloc of countries has become one of the fastest-growing regions in the world.
CIMB said in a statement it will operate a 100-percent owned subsidiary with headquarters in Phnom Penh.
Phnom Penh Sugar is owned by Ly Yong Phat, a powerful senator for the Cambodian People’s Party.
The delegation included three Khmer monks who had spent about one year in jail each in Vietnam.
The agreement, which is expected to spur trade, tourism and other activities in Cambodia.
China has pledged to provide military aid, including more than 250 trucks, exceeding a previous aid scrapped by the US.
The land dispute in Kampong Speu underscores the difficulties arising throughout Cambodia.