It is not solvency, or the lack of capital – a vague, synthetic, and usually quite arbitrary concept, determined by regulators – that kills a bank; it is – as Dick Fuld will tell anyone who bothers to listen – the loss of (access to) liquidity: cold, hard, fungible (something Jon Corzine knew all too well when he commingled and was caught) cash, that pushes a bank into its grave, usually quite rapidly: recall that it took Lehman just a few days for its stock to plunge from the high double digits to zero.