Complex sentence: In the late 1950s, ethnic Chinese comprised 70% of Bangkok's business owners and senior business managers and to 90 percent of the shares in Thai corporations are said to be held by Thais of Chinese extraction.
Split into simpler sentences: In the late 1950s, ethnic Chinese comprised 70% of Bangkok's business owners and senior business managers. Up to 90 percent of the shares in Thai corporations are said to be held by Thais of Chinese extraction.