China's apparent breakthrough in AI and rapprochement with tech giants has sent Hong Kong stocks and internet giants soaring, but the buyers behind it are flighty and brokers say global investors are wary of big bets while markets swing wildly.

Hong Kong's Hang Seng has roared back from a run of lean years to vie with Germany's DAX as the world's best-performing market for the year so far, with gains of 13% and 13.1% respectively, against a 4% rise for the S&P500.

Hong Kong tech shares have surged 31% since the middle of January to hit three-year highs on Monday while President Xi Jinping sat down with top tech leaders in Beijing.