We are huge fans of stress tests. In many ways, they are the best macroprudential tool we have for reducing the frequency and severity of financial crises.

The idea behind stress tests is simple: see if all financial institutions can simultaneously withstand a major negative macroeconomic event—a big fall in real output, a large decline in equity and property prices, a substantial widening of interest-rate spreads, an adverse move in the exchange rate. And, importantly, assume that in response to these adverse circumstances banks have no way to sell assets or raise equity. That is, the stress test asks whether each intermediary can stand on its own without help in the middle of an economic maelstrom. But for stress tests to be effective, they must be truly stressful. The tempest has to be the financial equivalent of a severe hurricane, not just a tropical storm.

This brings us to the latest European Banking Authority (EBA) 2016 stress tests. As we mentioned recently, the European financial system may be the biggest source of systemic risk globally. So, these tests are important not just for Europe, but for the world as a whole. Unfortunately, they just aren’t severe enough, so there is little reason to be confident about the resilience of European finance...