Two American self published nonfiction authors I know reported large purchases of new books earlier this year, more than 50 units at a time, via Amazon. This is unusual because the books are not well known. Because the books do not sell well otherwise, they were very few used copies available for sale on Amazon.

Here's my AI theory: someone is purchasing lots of books en masse to be packaged and sold for LLM training to multiple clients (not just a single company like Anthropic), but only scanning once and then reselling the scans while preserving a "chain of custody" proof that individual copies were purchased. Claude shot that idea down for reasons related to the intricacies of US first sale doctrine and copyright law, but had an ambiguous response when I proposed that it might be Chinese companies doing something similar for training AI models that are intended for possible resale to overseas markets.