CHINA’S TWO TECHNOLOGY giants are mostly homebodies. Unlike Alphabet’s Google, Amazon and Facebook, which rely on overseas markets for a third or more of their total sales, Alibaba and Tencent collect only a small fraction of their revenue outside of China. But a different story is unfolding in Southeast Asia where, over the last several years, Alibaba and Tencent have spent billions of dollars to secure major equity stakes in the region’s leading tech startups. Investments from the two Chinese giants have stimulated growth and expansion, but have also forced changes in leadership and strategy.