The impact of impact investing
研究了ESG撤资对目标公司资本成本的影响，发现当前撤资策略对资本成本影响太小，不足以改变实际投资决策，建议社会意识投资者应投资并行使控制权来改变公司政策。
We evaluate the quantitative impact of ESG divestitures. For divestitures to have impact they must change the cost of capital of affected firms. We derive a simple expression for the change in the cost of capital as a function of three inputs: (1) the fraction of socially conscious capital, (2) the fraction of targeted firms in the economy and (3) the correlation between the targeted firms and the rest of the stock market. Given the current state of ESG investment we find that the impact on the cost of capital is too small to meaningfully affect real investment decisions. We empirically corroborate these small estimates by studying firm changes in ESG status. When firms are either included or excluded from the leading socially conscious US index (FTSE USA 4Good) we find no detectable effect on the cost of capital. We conclude that current ESG divesture strategies have had little impact and will likely have little impact in the future. Our results suggest that to have impact, instead of divesting, socially conscious investors should invest and exercise their rights of control to change corporate policy.