Multiplier effects in economies with missing risk markets

The paper analyses the impact of pecuniary externalities in a two-sector economy with an incomplete market structure. Agents in each sector choose their proportion of risky investment. Sector specific risks are assumed to be perfectly negatively correlated. It is shown that the economy is more volatile if risk markets do not exist. With a complete set of risk markets, shocks in one sector will be dampened on the aggregate level. In contrast, when risk markets are absent, pecuniary externalities arising from higher risky investment in one sector can create feedback effects in the other sector. When agents are sufficiently risk averse (their coefficient of relative risk aversion being greater than one), an individually optimal response to the increased riskiness of the price distribution will result in an even riskier price distribution: an increase in risky activity in one sector will lead to an increase in risky activity in the other sector, and this gives multiplier effects.