For a party that isn’t a litigant in the case, Apple has an intense interest in the penalty phase of the landmark U.S. vs. Google antitrust trial.

Apple’s interest is so great in the U.S. vs Google antitrust trial that it tried to join the penalty phase of the case as a co-defendant with Google.

Its concerns burst into the open on Wednesday during testimony from Apple executive Eddy Cue, who said that Google searches through Apple devices declined for the first time ever in April. He blamed a new crop of AI search tools like Perplexity and ChatGPT.

Alphabet stock was the main casualty of the comments, finishing Wednesday down 7.3%. But Apple has something at stake in this trial too. It gets billions of dollars every year from Google—profits that are now at risk in the trial.

Apple shares finished Wednesday down 2.3%. 

It’s impossible to analyze Cue’s testimony without recognizing Apple’s self-interest in the outcome of the case. 

The trial has focused on the steps that Google took to maintain its monopoly in U.S. search engines, including the payments it sends to Apple for making Google Search the default on its products. As revealed at trial, over half of U.S. Google searches begin on an Apple device. In 2022, Google’s payments to Apple amounted to $20 billion, or 18% of Apple’s total pretax earnings that year.

Google ultimately lost the trial, and it’s now dueling with the Department of Justice over what penalties it will face. One Justice Department proposal would prohibit Google from making payments to guarantee search placement. Ironically, that remedy is a bigger loss to Apple, which would forfeit billions in profit, than to Google, which would immediately save billions. Its 2022 payment to Apple was roughly 10% of its total overall costs.

Apple’s interest is so great here that it tried to join Google’s case as a co-defendant in the penalty phase. Apple told the Court that the Justice Department’s proposal “threatens to undercut Apple’s property interest in its existing contract with Google and in its ability to enter into future contracts with Google across a host of domains, including general search, AI, and other related areas.”

Apple’s request was denied, which left Cue in an unusual spot on Wednesday, as a witness that wanted to be a defendant. His testimony, therefore, has to be seen through Apple’s broader interest in the case. His comments on falling search traffic, even if true, may be an attempt by Apple to show Google’s search dominance is already fading, and that it deserves more lenient treatment from the Court.

Apple has 20 billion reasons to make that argument, even if it also helps Google in the process.