Authors are earning less from Amazon’s new pay-per-page model than they should be, thanks to a rash of scammers taking advantage of the company’s self-publishing platform.

The scammers are exploiting a loophole in Amazon’s Kindle Unlimited service – which allows subscribers to read an unlimited number of books for a flat monthly fee – to earn much more money from short books than they ever would if they were sold fairly.

The heart of the scam revolves around Amazon’s new strategy of paying authors for every page read through Kindle Unlimited . Announced in June 2015, the change was unpopular among many authors who saw their revenue from Amazon slashed overnight.

Previously, authors were paid a flat fee for every reader who downloaded their book – typically around $1.30 (89p) per book. But after the change was introduced, they were instead paid six tenths of a cent for each page read, meaning that an author would have to write a 220-page book, and have every page read by every person downloading it to earn the same amount they previously got.

In practice, however, Amazon isn’t able to judge whether or not a reader has truly read a book, and so the company judges how much of the book has been read by the latest syncing position received by its servers. In other words, a reader who opens a book and skips to page 400 would be judged as having “read” 400 pages – and the author paid accordingly.

Typically, a reader would have little reason to do that. But a number of enterprising scammers have uncovered several ways to encourage them to do just that, according to the New York Observer. One method covered by the magazine involves selling the book in a number of different languages (typically machine-translated), with the English edition put at the very back of the book.

Amazon is clearly aware of the scam, because authors who accidentally encourage similar behaviour have found themselves banned. The New York Observer cites Walter Jon Williams, whose book Metropolitan (published in 1995) has the table of contents at the back of the book. When Williams ran a paid ad campaign, Amazon noticed and forced him to change the layout before it could be purchased again.

But many of the books that aren’t waved under Amazon’s nose are never discovered by the company. And because of the unique way authors are paid under the Kindle Unlimited scheme, it doesn’t have much motivation to look too hard for the scammers.

All the authors who choose to make their books available on Kindle Unlimited are paid, not a flat rate for each page read, but a portion of funding pool that Amazon provides. The size of the pool fluctuates, from $11m last summer to $15m last month, but it’s set by Amazon. No matter how successful the scammers are, Amazon doesn’t lose any more or less than the $15m it sets aside to pay Kindle Unlimited authors.

But other authors do lose out. The same pool goes to pay more “pages read”, reducing the fee for each individual page read.

When Amazon moved to per-page-read payments, authors speculated that the change was intended to cut out erotica authors, who tended to publish short serialised works, in an effort to improve the composition of its bookstore. In hindsight, that looks to have backfired.

Amazon did not respond to requests for comment on this story, but gave the following statement to the New York Observer: “It’s important to us to ensure that customers can trust our sales’ rankings and that those rankings accurately reflect legitimate customer activity. So as not to reveal anything to potential abusers, we don’t discuss the specifics of the tools we use to check for abuse, and we are constantly working to improve them.”