When large Japanese companies were looking at Thailand for business expansion opportunities, they needed the right facilities and infrastructure. That’s when the Sumitomo Realty Group met Dr. Prasert and Dr. Yada Sombuntham. A friendly relationship ensued between the two entities, and soon they became partners. Dr. Prasert and Sumitomo combined to build the first Thaniya Building in 1970. The first tenants were Sumitomo Trading and Bank of Tokyo. Soon they were joined by other Japanese companies, golfing shops, bookshops and restaurants. This building was refurbished in 2006 and the structure now connects with Bangkok’s ultra- efficient Sky Train, and is presently known as Thaniya BTS Building.