US stock futures fell on Monday as a warning from artificial intelligence developer Anthropic spooked technology traders, with the Dow, S&P 500 and Nasdaq all pointing lower. Oil prices jumped at the same time, adding to the cautious mood across global markets. The combined pressure on equities underscored how quickly sentiment can shift when the AI trade, which has driven much of this year's market gains, meets a fresh note of caution.
Anthropic's warning landed at a delicate moment for investors who have poured money into AI-linked companies on the expectation of rapid commercial adoption. Technology stocks have been the main engine of the broader market's advance, so any signal that the AI boom could face obstacles tends to ripple through index futures before the cash session even opens. The rise in crude prices compounded the unease, reviving concerns about input costs and the wider inflation picture at a time when central banks are still weighing the path of interest rates.
The market reaction reflects a broader reassessment of how AI is reshaping established industries, and not always to the benefit of incumbent players. New research published in recent weeks shows that AI-generated books are flooding online marketplaces at a scale that is beginning to affect the earnings of human authors. An Originality.AI report found that of more than 2,000 books on religion listed on Amazon over the past 12 months, 1,272 titles, or 63%, were flagged as likely written by large language models.
A separate study led by Stony Brook University examined 14,419 self-published genre-fiction books sold on Amazon between 2023 and 2026 and run through AI-detection software Pangram. It found that 2,880 titles, about 20%, contained substantial AI text, meaning more than a quarter of the prose was flagged as machine-generated. A further 2,168 books had more than half of their prose flagged, and nearly 1,000 novels were more than 90% AI-generated. The study has not yet been peer-reviewed.
Critically for the publishing business, the influx of AI titles appears to be diluting revenue rather than expanding the market. Over the three-year period studied, the number of books with observed sales in a quarter rose 19.2-fold, but quarterly revenue increased only 8.9-fold, pointing to a sharp fall in revenue per title sold. Researchers attribute the gap to a crowding-out effect: the sheer volume of AI-generated books makes it less likely that a customer will choose a human-written title, reducing sales and income for authors.
«The crowding-out effect generated by these books — most of which are low quality, but some of which are still good enough that they lead to higher ranks — due to this increased competition, they're likely to get squeezed, and their revenues are reduced,» said Paramveer Dhillon, an associate professor of information at the University of Michigan and a co-author of the study.
Amazon requires self-published authors to disclose whether they have used AI to generate text and limits uploads to three titles per day. A spokesperson said the company is «committed to a bookstore that readers love and publishers and authors trust,» adding that content guidelines govern which books can be listed and that proactive and reactive measures are used to detect and remove violating content, whether AI-generated or not.
Tuhin Chakrabarty, an assistant professor of computer science at Stony Brook University and a co-author, pointed to the «algorithmic bubble» of online marketplaces as part of the problem. More AI books increase the likelihood that customers click on and buy machine-generated titles, which in turn pushes those titles higher in search and recommendation listings. As AI writing improves, the quality gap may narrow further, making the competition tougher for unknown human authors whose work may no longer surface in related-book listings.
Authors have responded with copyright litigation against AI companies including OpenAI, Meta, Anthropic and xAI, alleging that their books were used to train models without permission. In July, a federal judge approved a $1.5 billion copyright settlement ordering Anthropic to pay thousands of authors after the company downloaded and stored millions of pirated books to train its chatbot Claude.
Booksellers are still working out how to respond. Barnes & Noble chief executive James Daunt said earlier this year that he would not outright ban AI-generated books provided their origins are clearly labelled, but noted that major publishers are unlikely to release such titles, making it improbable the retailer would stock them. «Our position is that we do not sell AI books, as far as we are aware; we take active measures to exclude all AI-generated books from our online catalogue and never knowingly order any for stocking in our stores; and we demand that publishers label any books that are AI-generated,» he said. «This is a straightforward rejection of AI books.»