William Felix Browder is an American-born British financier and political activist. He is the CEO and co-founder of Hermitage Capital Management, the investment advisor to the Hermitage Fund, which at one time was the largest foreign portfolio investor in Russia. The primary investment strategy of Browder was shareholder rights activism. Browder took on large Russian companies such as Gazprom, Surgutneftegaz, Unified Energy Systems, and Sidanco. In retaliation, on November 13, 2005, Browder was refused entry to Russia, deported to the UK, and declared a threat to Russian national security.