Matrix Metrics: Network-Based Systemic Risk Scoring I propose a novel framework for network-based systemic risk measurement and manage-ment. I define a new systemic risk score that depends on the level of individual risk at each financial institution and the interconnectedness across institutions, and is generally applica-ble irrespective of how interconnectedness is defined. This risk metric is decomposable into risk contributions from each entity, forming a basis for taxing each entity appropriately. We may calculate risk increments to assess the potential risk of each entity on the overall finan-cial system. The paper develops other subsidiary risk measures such as system fragility and entity criticality. An assessment using a measure of spillover risk is obtained to determine the scale of externalities that one bank might impose on the system; the metric is robust to this cross risk, and does not induce predatory spillovers. The analysis suggests that splitting up too-big-to-fail banks does not lower systemic risk.