Here is Duffie’s recommendation for how to make the tri-party clearing system more stable:
Given the systemic importance of tri-party clearing agents, and given their high fixed costs and additional economies of scale, tri-party repo clearing services for U.S. dealers and cash investors should probably operate through a dedicated regulated utility. Although this would likely increase operating costs for market participants, it would enable investment in more advanced clearing technology and financial expertise, allowing greater resilience of the tri-party repo market in the face of financial shocks such as the default of a major dealer. The moral hazard associated with lending of last resort to a dedicated utility is much reduced relative to the case of a financial institution with a wide scope of risk-taking activities.