This article argues that the driving force behind the structured credit products that triggered the financial crisis was a global excess demand for securities, and that key to the build-up of this demand was the huge accumulation of private wealth. The argument is Marxian inasmuch as it builds on Marx's insight that crisis is endemic to capitalism because the commodity form by its very nature gives rise to the possibility of a separation between supply and demand, and because periodic realization of this separation arises out of the fact that the value of the labour capacity is generally less than the value of the output produced by it. The argument is an unorthodox Marxian one in that its specification of the mechanism through which the effects of exploitation feed into crisis is different from that specified by Marx himself. While the separation between supply and demand is central to the crisis transmission mechanism described here, the difference is that the commodities in question are financial commodities rather than material commodities. Prevented from surfacing ‘below’ in GDP space in the form of an excess supply of material goods, the effects of exploitation have instead surfaced ‘above’ in capital market space in the form of an excess demand for debt securities.