What happens to environmental, social and governance-oriented investment in a market shock? We’re about to find out. Socially responsible investing, which has become a feature of the financial landscape and a $30 trillion-plus industry, came of age long after the last major financial crisis. Expect a welcome dose of scrutiny.

So far, it hasn’t been pretty. By early Thursday, the Bloomberg SASB US Large Cap ESG Index had dropped almost 21% from a peak Feb. 19, a steeper fall than the S&P 500 Index. The MSCI World ESG Leaders Index dropped almost 19%, roughly in line with the broader MSCI World. The heftiest ESG funds by and large did better, though only narrowly.

This isn’t a huge surprise: Many such funds track the benchmark, and then tilt toward more ESG-friendly companies. They are unlikely to react in a dramatically different way to a widespread market shock, especially one that batters both supply and demand. That’s true for all but the most active managers, and probably only if they have shied away from polluters including big drillers, airlines, cruise companies and the like, all of which have been badly hit by the coronavirus and the subsequent oil crash.

It does, though, raise an uncomfortable question. What happens to ESG when doing good isn’t — at least momentarily — the same as doing well?

ESG investing has leaned heavily on the credible premise that companies scoring well on factors such as diversity, health and safety, and managing carbon risk will do better than peers. Who cares wins, in the words of the United Nations Global Compact. It’s a sensible idea well-supported by research. Yet ESG is untested in times of extreme stress, when short-term market ructions will strain market participants, however lofty their longer-term objectives. We simply don’t know how investors and fund managers will behave, or how firms will act when really squeezed.

What’s at stake isn’t ESG performance per se. It’s a long-term investment philosophy that focuses on backing companies that are, by virtue of how they are run and what they produce, more resilient to climate, social and other change. How a fund performs in a bad patch probably doesn’t say much about the multi-decade resilience ESG is supposed to promote. Conversely, a capital exodus that has seen tens of billions wiped off the value of energy companies, and especially the U.S. shale industry, isn’t a clear win for ESG.

Yet for investors, today’s market problems can dwarf tomorrow’s green ones, especially if the virus and oil crunch turns into financial cataclysm.