By Patience Haggin

The Daily Mail's owner filed an antitrust suit against Alphabet Inc.'s Google on Tuesday, alleging the tech giant manipulates search results and advertising auctions in ways that harm online publishers.

The suit, filed in Manhattan federal court, alleges that Google punishes publishers in search rankings if they don't sell enough advertising space through Google's marketplace.

The Daily Mail's concerns stem in part from its assessment that its coverage of the U.K.'s royal family in 2021 has been played down in Google's search results, a spokesman for the publisher said.

A Google spokeswoman didn't immediately respond to a request for comment.

Publishing executives complain in private about Google's dominance of search and advertising, but few go public with their grievances. In January, the parent company of West Virginia's Charleston Gazette-Mail filed an antitrust suit against Google and Facebook Inc. Several other small publishers on Monday filed suits against those two tech companies, citing a deal between them code-named "Jedi Blue."

Separately, Google is facing antitrust suits brought by the U.S. Justice Department and attorneys general in several states. The company has denied abusing its market power and has said the ad technology market is competitive.

The U.K.-based Daily Mail, known for celebrity and pop-culture news, has built one of the world's most-read websites, with 75 million unique monthly visitors in the U.S., according to the suit, which seeks unspecified damages. The suit also asks Google to discontinue its alleged misconduct and offer transparency into its news-search algorithm.

Publishers have a complicated relationship with Google. The tech company's search engine is a major source of web traffic for many sites, and most of the industry uses Google software to sell ad space in advertising exchanges. But Google also competes with publishers for online ad dollars and supplies tools to ad buyers. Google had a nearly 29% share of the U.S. digital ad market in 2020, according to research firm eMarketer.

In the suit brought by the Mail's owner, Associated Newspapers Ltd., and its U.S. unit, Mail Media Inc., the publisher alleges Google linked its search engine and ad-sales platform to put pressure on publishers, abusing its market power.

In 2019, Google punished the Daily Mail in its search results because the publisher had configured its online ad sales in a way that sent its business away from Google in many instances, according to the complaint. Google later tweaked its technology to counteract that tactic and restored the Daily Mail's normal search performance, the suit alleges.

More recently, Daily Mail executives have been disappointed that the site's coverage of the royal family has not shown up prominently in search results for keywords such as "Meghan and Harry," "Piers Morgan" and "Prince Philip," the spokesman for the publisher said.

The suit alleges Google has given its online exchange special advantages over rivals in auctions of advertising space. It cited "Project Bernanke, " a secret program referenced in a Texas lawsuit against Google that allegedly allowed the company to gain insight into the bidding behavior of competitors. Google has acknowledged the existence of the program but has denied it was inappropriate, saying rivals have used comparable techniques.

The Daily Mail's suit also alleges that Google's plan to phase out "cookies" -- bits of code used to track users on the web -- in its Chrome web browser will make it more difficult for advertisers to target ads unless they buy through Google's systems. Google has said it is making the change to protect user privacy.

Even as they fret about Google, many publishers are eager to license news stories to the tech giant in exchange for a fee. Google has begun licensing news for its Google News Showcase product. Daily Mail hasn't accepted any money from News Showcase, according to a person familiar with the matter.

Write to Patience Haggin at patience.haggin@wsj.com

(END) Dow Jones Newswires

04-20-21 0951ET