ByteDance, the Chinese owner of TikTok, plans to buy back up to $6 billion in shares from existing investors at a valuation of about $400 billion, according to a shareholder letter and a person familiar with the matter cited by The Information. That valuation is 20% above the level used in the company’s previous buyback a year ago. The increase follows a January deal with the Trump administration intended to prevent a U.S. ban on TikTok, under which ByteDance sold an 80% stake in the app’s U.S. data-security operation to an American-owned joint venture while retaining its revenue-generating operations.