The rise of AI-written fiction book sales on Amazon, 2023-2026

A new study analyzing 14,419 self-published genre fiction ebooks on Amazon found that one in five books now contains substantial AI-written text, and the average human-written book earns less per title than in 2023 in seven of eight genres. Researchers used Pangram full-text AI detection to classify books and found that the more AI books enter a genre, the more ground non-AI books lose, with their hold on top-chart spots sliding from 88% in least-AI genres to 63% in most-AI genres. The paper, which speaks to copyright litigation in Kadrey v. Meta, shows that AI-written books reuse rare phrases at twice the rate of successful non-AI books and often have verbatim overlap with other AI books.

🚨 New paper on AI and Copyright 🚨 It's easy to dismiss AI-written books 📚 as slop nobody buys. So, armed with full-text AI detection from - How we did it 📊: We randomly sampled 14,419 self-published genre fiction ebooks less gatekeeping and low barrier to entry and ran Pangram on the full-text to classify each book as substantial AI 25% , light AI <25% and no-AI 0% . Then we matched each book to aBooks with substantial AI text are now everywhere: 1 in 5 books in our sample, across every genre - romance, thrillers, sci-fi, all of it. The typical book written with AI sells far fewer copies than the typical non-AI one. But there are so many of them that as a group they'veHere's the imbalance at the heart of the paper. Over 3 years, the books catalog grew 38x cumulatively. The book's revenue? Only 9x quarterly. Way more books fighting over a pie that barely grew which means the average book earns less than it used to. 4/n "Sure, but doesn’t it mean that cheap AI books are dragging the average down?" No, and this is our key result. No-AI books, on their own, earn less per book than they did in 2023 in 7 of 8 genres. The one genre where human authors are doing better +35% is Fantasy/horror whichThe more AI books enter a genre, the more ground non-AI books lose. Their hold on the top-chart spots slides from ~88% in the least-AI genres to ~63% in the most. And it's the worst in Kindle Unlimited-heavy genres since KU readers draw from one shared subscription pool, so everyThe million dollar question : Who's producing these books? Authors who, once they started producing with AI, didn't stop but instead accelerated. Among those who kept at it, 3 in 4 published faster than before, some hitting dozens of books a year. The monetary earnings areAnd the AI books that succeed share a signature. They contain noticeably more rare phrases that already appear in published books than successful non-AI books do.Award-winning literary fiction, for comparison, reuses rare phrasing at less than half their rate. 8/n What’s funny is that AI is causing mode collapse : A lot of AI-written books have verbatim overlap from other AI books. Can this serve as an alternative evidence to AI-detection skeptics ? 9/n 👨⚖️ TL;DR: AI doesn't need to write high-quality books for non-AI book writers to get hurt. Cheap books at massive volume are enough and they've cut what the average human-written book earns in most genres and pushed human titles down the bestseller ranks. 10/n Our results also speak directly to a copyright question that is being litigated right now: whether AI outputs compete with the very works the models are trained on. In Kadrey v. @Meta https://x.com/Meta , Judge VinceChhabria spoke about market dilution and flagged this as the harm that could beOur paper can be found at the link below : arxiv.org/pdf/2607.20349 https://arxiv.org/pdf/2607.20349 Anonymized data and code coming soon. Stay Tuned. Many many thanks to friends at @pangram https://x.com/pangram @max spero https://x.com/max spero @kthai1618 https://x.com/kthai1618 @bradley emi https://x.com/bradley emi @jennajrussell https://x.com/jennajrussell for their encouragement and support with this research 💕 Join the conversation