Rule 5: Decision makers must have skin in the game.

At no time in the history of humankind have more positions of power been assigned to people who don’t take personal risks. But the idea of incentive in capitalism demands some comparable form of disincentive. In the business world, the solution is simple: Bonuses that go to managers whose firms subsequently fail should be clawed back, and there should be additional financial penalties for those who hide risks under the rug. This has an excellent precedent in the practices of the ancients. The Romans forced engineers to sleep under a bridge once it was completed.

Because our current system is so complex, it lacks elementary clarity: No regulator will know more about the hidden risks of an enterprise than the engineer who can hide exposures to rare events and be unharmed by their consequences. This rule would have saved us from the banking crisis, when bankers who loaded their balance sheets with exposures to small probability events collected bonuses during the quiet years and then transferred the harm to the taxpayer, keeping their own compensation.