Tiong Hiew King founded the timber company Rimbunan Hijau Group in 1975. The group has forestry concerns in 16 countries, as well as interests in palm oil, oil and gas and property. He is also heavily involved in the Chinese Malaysian media, both print and digital, and he owns four daily newspapers that comprise 70% of that market.

Away from the region, he owns the Oregon Group. Based in New Zealand, it is the second largest private landowner in the country and builds both residential homes and hotels. It is also involved in the manufacture of plastic containers and the farming of salmon.