A federal judge blocked a bid on Oct. 31 by Penguin Random House, a multinational publishing company, to buy one of its biggest competitors, Simon & Schuster.

U.S. District Court Judge Florence Pan cited the Department of Justice’s claim that the merger would stifle competition in the book-selling industry. The decision came as a triumph for U.S. President Joe Biden’s administration, which has taken a more aggressive approach to antitrust enforcement than preceding administrations.

“Today’s decision protects vital competition for books and is a victory for authors, readers, and the free exchange of ideas,” Assistant Attorney General Jonathan Kanter, who is part of the justice department’s antitrust division, said in a press release.

Judge Pan echoed this sentiment in an order, saying that the justice department demonstrated that the merger violates antitrust laws. She also said the merger might “substantially” harm competition in the U.S. market for publishing rights to top-selling books.

The full order that contains Pan’s reasoning is temporarily sealed due to it possessing “highly confidential information.” It will be released after both parties file redactions.

Penguin Random House and its parent company, Bertelsmann, announced on Oct. 31 that they were seeking an expedited appeal. They called the ruling “an unfortunate setback for readers and authors.”

“The Department of Justice’s focus on advances to the world’s best-paid authors instead of consumers or the intense competitiveness in the publishing sector runs contrary to its mission to ensure fair competition,” the publisher added, as reported by PBS NewsHour.

Penguin Random House and Simon & Schuster are two of the “Big Five” companies in the publishing industry, alongside comparable powerhouses Macmillan Publishers, Hachette Book Group and HarperCollins Publishers.

The Big Five publishers control nearly 80% of the trade market for print books in the United States. Penguin Random House holds the biggest slice of the pie, with a market share of 25% in 2020.

ViacomCBS, which is the parent company of Simon & Schuster, put the publisher for sale in 2020, with Penguin Random House and HarperCollins emerging as the leading bidders. Penguin Random House won out with a reported bid of $2.2 billion.

A publishing house made of both Penguin Random House and Simon & Schuster would have dominated the industry in an unprecedented way. At the time, however, no one anticipated thatthe former U.S. President Donald Trump’s administration would counter it.

”I’m pretty sure the Department of Justice wouldn’t allow Penguin Random House to buy us, but that’s assuming we still have a Department of Justice,” Simon & Schuster CEO Jonathan Karp told an author in an email.

The trial, which unfolded over three weeks in August in the U.S. District Court for the District of Columbia, was closely watched by the literary world.

The outcome was expected to serve as a measure of success for the government’s latest effort to curb consolidation. It was also expected to serve as insight into the future of the publishing industry, which has been rocked by mergers in recent years.

Representatives from other major publishing houses, such as HaperCollions and Hachette, testified against the deal.

Another witness present at the trial was author Stephen King, who testified in favor of the Department of Justice. King expressed concern that the merger would be especially detrimental to new writers, despite his own publisher, Scribner, being a part of Simon & Schuster.

“Further consolidation would have caused slow but steady damage to writers, readers, independent booksellers, and small publishing companies,” King told The New York Times.

“Publishing should be more focused on cultural growth and literary achievement and less on corporate balance sheets.”