This is a paper about language variation and about language change, investigating the competition between the s-genitive and the of-genitive in Modern English (written and spoken, British and American) as a case study. Drawing on a range of spoken and written corpora and considering a multivariate envelope of seven major conditioning factors (such as possessor animacy and end-weight), the paper seeks to uncover, first, how the probabilistic preferences of British and American journalists might have changed between the 1960s and 1990s, and, second, how such changes in written English relate to the way speakers of English choose between the two genitives. It is found that the s-genitive is comparatively frequent in both spoken English and contemporary journalistic English thanks to quite different reasons, and that the recent spread of the s-genitive in press English is due to a process of economization rather than colloquialization.