Post crisis, the focus has increasingly moved to market based measures both because of the availability of higher frequency data and the fact that such data is usually forward looking and reflects the market expectation of the future performance of the underlying institutions.
Different sets of models have been developed using equity prices, CDS prices, CDO indices, LIBOR spreads, etc., as proxies for systemic risks, employing techniques such as econometric analysis including Principal Component Analysis to derive the systemic risk measure.