Foreign investors are plotting a return to China's stock markets in a big way three years after pulling back and terming them uninvestable, encouraged by the tech opportunities on offer, and a growing demand for diversification beyond U.S. assets. Progress in China's adoption of artificial intelligence and its development of semiconductors and innovative drugs this year has given comfort to global investors that the Sino-U.S. trade war and Washington's tech export bans have not deterred innovation in the world's second-biggest economy. The U.S.-China tariff truce and a domestic monetary easing environment have further boosted sentiment. As a consequence, the Shanghai Composite index touched a decade high last week while Hong Kong stocks hit a four-year high.