ChainCatcher news, Tether's comprehensive financial data for the first quarter of this year shows that as of March 31, its direct and indirect holdings of U.S. Treasury securities amounted to as much as $91 billion. Meanwhile, the company also holds $5.4 billion worth of Bitcoin. According to Treasury data from March, Tether is the 19th largest holder of U.S. Treasury securities among sovereign nations, positioned between South Korea and Germany. In response, former House Speaker Paul Ryan has called for regulation of stablecoins, as the U.S. Treasury securities held by Tether underpin the digital fortress of the dollar.