Apple stock reached a new intraday high of $237.49 on October 15, but analysts are sounding a note of caution.

Google’s parent company, Alphabet (GOOGL) , is under intense regulatory scrutiny. U.S. regulators are zeroing in on Google’s deal with Apple  (AAPL)  to make its search engine the default on iPhones and other Apple devices.

???? Don’t miss the move: SIGN UP for TheStreet’s FREE Daily newsletter ????

The arrangement has been a lucrative source of revenue for Apple. Google pays Apple between $18 billion and $20 billion a year, accounting for 14% to 16% of Apple's annual operating profits, Bernstein said in a recent report, The Register reported.

But as the DOJ pushes forward with its antitrust case against Google, Apple’s financial stake in this partnership may be at risk.

"We believe there is a possibility that federal courts rule against Google and force it to terminate its search deal with Apple," said Bernstein.

Related: Analyst issues bold Apple stock forecast after iPhone disappointment

Regulators argue that Google’s default status on Apple devices stifles competition by limiting other search engines' opportunities. Should the DOJ win, it could restrict Google’s agreements, preventing exclusivity arrangements with Apple.

Analyst says Apple could lose a third of Google revenue

Investment firm Jefferies warns that a DOJ victory could result in Apple losing a crucial revenue stream.

"The antitrust expert hosted by our US Internet team believes it could take 3 to 8 years to settle," analyst Edison Lee wrote in a note, Seeking Alpha reported. "We estimate if AAPL loses 1/3 of GOOG revenue (U.S. only) as of FY28, our DCF will be ~8% (US$19) lower."

Related: Nvidia's biggest problem might be about to get even worse

Lee, who has a hold rating on Apple, noted that while the revenue impact would only affect U.S. earnings, a ruling against Google in the U.S. could have a ripple effect globally.

This could prompt regulators in other countries to consider similar antitrust measures, potentially impacting Apple’s Services revenue from Google outside the U.S.

Apple's Services segment reached a record $24.2 billion in its fiscal Q3, driven by strong cloud, payment, and advertising services performance.

Despite that overhang, Lee views the iPhone 16 and the upcoming Apple Intelligence rollout as more critical near-term drivers for Apple.

The iPhone remains Apple’s largest revenue generator, making up roughly 46% of the company’s total sales in the most recent quarter.

On Aug 1, Apple shared that the segment brought in $39.3 billion in the fiscal third quarter ending June 29, reflecting a 1% year-over-year drop but coming in above the $38.81 billion forecast.