Chipmaker CXMT overtook Tencent to become China's most valuable public company today, with a market cap of CNY3.5 trillion (USD519 billion). The company's stock [SHA: 688825] closed 1.2% lower at CNY52.9 (USD7.80), while Tencent [HKG: 0700] ended down 4.5% at HKD441 (USD56.20), valuing it at HKD4 trillion (USD510 billion), after the internet giant released financial results late yesterday.