SRISK

SRISK (Systemic Risk) is a measure of the expected capital shortfall of a financial institution conditional on a systemic crisis, developed by Viral Acharya, Lasse Pedersen, Thomas Philippon, and Matthew Richardson in 2012. Unlike traditional risk measures that focus on individual firm distress, SRISK quantifies each firm's contribution to the aggregate capital shortfall of the financial system during a severe market downturn.

The SRISK of a firm is defined as its expected equity loss in a systemic crisis scenario — typically modeled as a 40% market decline — minus its current capital buffer. A firm with high leverage and large market capitalization will have high SRISK because its absolute equity loss in a crisis will be large, and because its size means that its distress will absorb more of the system's recapitalization resources. The aggregate SRISK across all institutions provides a time-varying index of systemic risk that has been shown to predict future financial instability better than firm-level risk measures.

SRISK is estimated using market data: equity prices, volatility, and balance-sheet leverage. The market-based approach has advantages over accounting-based measures. Market prices reflect forward-looking expectations about future losses, and they update continuously rather than quarterly. But market prices also reflect investor beliefs that may be systematically wrong — during bubbles, SRISK may be understated because market prices overstate the value of equity; during panics, SRISK may be overstated because fire-sale pricing destroys market value that would recover in equilibrium.

The measure connects to the broader theory of systemic risk through its emphasis on size and leverage. SRISK formalizes the intuition that systemically important institutions are not merely those that are likely to fail, but those whose failure would be costly to resolve. This connects to the too