I'm not sure that a market crash is a prima facie bad thing. Market crashes often precede or accompany economic recessions but I'm inclined to believe that they

I'm not sure that a market crash is a prima facie bad thing. Market crashes often precede or accompany economic recessions but I'm inclined to believe that they are a symptom or result rather than a cause. An economic recession is a bad thing due to increased unemployment, among other reasons. If there is a real contraction in the health care sector and people react by pulling out of the market entirely then that is a good thing for people looking to put money into the market; the rest of the market is on sale (relative to its "real" value). Even if the market is made up entirely of indices, the market as a whole will end up appropriately priced. Those who panic sell will lose money but the index will bounce back assuming non-health care assets truly were undervalued.