Tencent's shares, traded in Hong Kong, have doubled in value this year as the tech company's earnings have repeatedly outmatched analysts' expectations.
A second stock connection with mainland China which opened late last year has allowed even more money to flow onto the semi-autonomous city's exchange.
By Tuesday afternoon Tencent's market capitalisation had reached 4.15 trillion Hong Kong dollars ($531 billion), surpassing the US social network's $519 billion.
Tencent has nearly one billion users on its popular WeChat phone platform, where people can chat, post photos, play games, transfer money and pay for a variety of services in China.
The must-have app has revolutionised China's tech industry, with even the media and publishing sectors seeing changes to how Chinese consume and pay for content.
Tencent's publishing-focused arm was spun off and listed in Hong Kong earlier this year.