Rather than focusing on individual firms politicians are now looking into laws and regulations that account for how important banks are to the stability of the network as a whole. Although stocks of capital can help banks rebound from a crisis, larger banks often hold less of it than smaller firms. They claim this isn't a problem because their investments are diversified and so less risky. But analysis of the financial ecosystem suggests otherwise: diversification doesn't necessarily protect large banks from collapse. Firms that are central to the system therefore need to hold enough capital to balance against potential losses.