This paper presents a dynamic model of Treasury markets, accounting for recent disruptions. We investigate the impact of various shocks on repo rates and Treasury yields and examine policy implications. Our findings highlight the crucial role of the reserves-to-outstanding Treasury securities ratio as a predictor of market disruptions and emphasize the importance of central bank balance sheet policies in maintaining stability. The model offers valuable insights for policymakers and serves as a foundation for future research on regulation and policy interventions in government securities markets.