ByteDance, the Chinese owner of TikTok, has seen its valuation surge to a record high of more than US$600 billion after a proposed equity sale from one of the founding shareholders, according to two sources familiar with the matter.The deal aimed to transfer US$900 million worth of ByteDance shares, one of the sources said.The seller originally had the company’s valuation at US$550 billion, in line with an earlier proposal by General Atlantic, one of the firm’s earliest institutional...