Legendary fund manager Li Lu (who Charlie Munger backed) once said, ‘The biggest investment risk is not the volatility of prices, but whether you will suffer a permanent loss of capital.’ So it seems the smart money knows that debt – which is usually involved in bankruptcies – is a very important factor, when you assess how risky a company is. We can see that Bouygues SA (EPA:EN) does use debt in its business. But the more important question is: how much risk is that debt creating?

When…