That's why it's not done. However that means something disastrous happens every few years. On average the company is better off, the increased profit in good ye

That's why it's not done. However that means something disastrous happens every few years. On average the company is better off, the increased profit in good years outweighs the losses in the possible bad year. It's where black swan theory comes in. How do you calculate the probability of a rare event?