Hat tip to Nate Hoffelder at The Digital Reader for bringing this story to my attention. It seems Pearson sent out an email this week to its customers announcing that watermarked ebooks will no longer be available from the MyPearson.com ebook store.

Effective immediately watermarked ebooks are no longer for sale, and watermarked ebooks that have been bought and paid for will be deleted on 30 April 2018.
Unless you are a student or otherwise involved in the education sector this won’t mean much, but it is a blow to those who have been relying on MyPearson.com for their digital educational materials.
Or rather, to some of them. Because VitalSource ebooks will still be available from the MyPearson store, as well as from the VitalSource website.