The family office of billionaire George Soros trimmed its stake in Liberty Broadband Corp. in the first quarter, according to a regulatory filing on Tuesday. Soros Fund Management's holdings of Liberty Broadband fell by 74,000 shares to just over 7.669 million as of March 31, remaining the portfolio's largest position, according to filings tracker Whalewisdom.com. The filing also reflected Soros's previously disclosed stake of nearly 21.5 million shares in Vici Properties Inc. , the fund's second-largest holding. Soros also increased his stake in Aetna by 346,585 shares, and boosted its holdings of Baxter International Inc. by more than 468,000 shares. Large investors are required to disclose long positions in stocks, options and convertible debt 45 days after the end of each quarter in 13F filings with the Securities and Exchange Commission.