Abstract
Twenty years on from the publication of the results of the celebrated M3 competition and we were just about used to the idea that there would be no more M-type competitions, when the M4 competition came along in 2019. A 4.0 earthquake is 10 times 'stronger' than a 3.0, and that was what M4.0 was aspiring to; so was its mission accomplished? (C) 2019 International Institute of Forecasters. Published by Elsevier B.V. All rights reserved.