As of June 1, this is the amount spent by BP to try to contain the oil spill that pollutes the Gulf of Mexico. However, the cost for BP goes far beyond. Between April 20, when the Deepwater Horizon oil rig collapsed, and June 1, BP’s shareholders have lost nearly $70 billion (that is, a 40% decrease of BP’s market capitalization).

How to explain such a loss? Basically, investors do not take into account only the direct costs of the disaster experienced by the company. They also anticipate a series of indirect costs: damage to the image, tighter regulations, cleanup costs, fines, etc. But as high as it is, the loss incurred by the shareholders is far from the social cost.

And even if this loss is substantially higher than in the case of previous similar accidents since 19901, it is unlikely to be sufficient to convince firms to adopt willingly much more stringent security measures.