Finance and Politics: Does the Stock Market Prefer the Left?

In the United States, stock market performance seems to be significantly higher when the Democrats are in power. Although tests are rarer, it seems that such a partisan premium also exists in France under the Left. The objective of this article is to verify whether the existence of such a premium is confirmed over the period 1981-2016 when the method used allows neutralizing the impact of the international conjuncture. The point of view is that of a US investor who manages an internationally diversified portfolio. The results confirm the existence of a partisan premium in favour of the Left.