Vanguard Group, the world's second-largest asset management firm, has reported significant unrealized losses on its holdings in Circle stock (CRCL). According to its latest 13F filing with the U.S. SEC, Vanguard holds 5,653,110 shares of Circle, valued at $339.4 million. This represents an unrealized loss of over $400 million, given the initial cost basis of $739.6 million. The disclosure comes as part of Vanguard's quarterly 13F filing, a requirement for institutional investment managers with over $1 billion in assets under management. These filings, which detail holdings as of the end of each quarter, are typically made public by mid-February for the previous year's fourth quarter.