Last year, the dispute between Amazon and the publisher Hachette inundated publishing news; now Amazon has gotten into a new fight over contract negotiations with the last of the “Big 5” publishers to sign a new contract: Penguin Random House UK.

According to The Guardian, the two companies are in a “dispute . . . that could grow into a full-blown row.” The contract under negotiation—which centers on internet sales—is the first contract since Penguin and Random House announced their merger in October 2012, and it terminates at the end of this month.

It’s unclear which terms the companies are disputing since different news sources are reporting, well, different news. (Philip Jones at The Bookseller says the terms being negotiated “relate to the revised agency deals put in place after a European Commission investigation four years ago,” while The Guardian reports that Penguin Random House is considering blocking Amazon from selling its books, or vice versa.)

In any case, the general consensus is that the fracas surrounding Amazon’s contracts with the other four of the Big 5 publishers is in response to the return of agency pricing, which allows sellers like Amazon to take a significant commission from book sales.

Penguin Random House spokesperson Claire Von Schilling’s statements to Re/Code about the dispute read neutrally: “We are in a continuous conversation with Amazon, with whom we have an ongoing business relationship. We have no intention whatsoever of ceasing to sell our print or digital titles on Amazon. We want our books to be accessible and available everywhere.”

Likewise, Amazon refuses to comment on the contract details, but its spokesperson Tarek El-Hawary said to Re/Code, “I can say that we have long-term deals in place already with the other four major publishers and we would accept any similar deal with Penguin Random House UK.”

In other news, The Guardian recently reported controversial tax practices by Amazon, which, until recently, booked its UK sales in Luxembourg for the past decade.