For decades, the US Treasury market has been the most liquid and resilient financial market in the world. Even in times of stress, Treasury securities were assumed to be tradable in large quantities, rapidly, and with little friction—a reliable anchor for the broader financial system. In recent years, however, this assumption has come under question. Severe market dysfunction, most notably in March 2020 but also in April 2025, shows that even the world’s safest securities market can seize up abruptly, with consequences far beyond government bond trading. […]