Specific countries fared worse than the average, with Russia losing 15% of its potential wheat crop, and Brazil, Mexico and Italy suffering above average losses.
There is no numerically specific definition of a crash but the term commonly applies to steep double-digit percentage losses in a stock market index over a period of several days.
The alternative, which some regulators prefer, is to create a specific layer of debt that would bear losses if a bank fails, without (it is hoped) triggering a run of all creditors.