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Shares of advertising tech companies Criteo (ticker: CRTO), Trade Desk (TTD), and LiveRamp Holdings (RAMP) were roiled this week as investors weigh potential privacy-related advertising changes to Google’s Chrome web browser and the search giant’s other properties.

Criteo is down 22% this week, Trade Desk is down 4.2%, and LiiveRamp is off 7.6%.

But Macquarie Research believes the potential changes are unlikely to be “a worst-case scenario” after the firm spoke with several ad tech and agency market insiders. Any changes that Alphabet’s (GOOGL) Google, the No. 1 digital ad company in the world, seeks are likely to “preserve third-party revenue streams as well as stay clear of anticompetitive issues,” Macquarie analyst Tim Nollen said in a research note Friday.

“We believe any discussions at Google remain internal, and worst-case scenarios are unlikely given commercial and regulatory scrutiny,” Nollen wrote. “We think RAMP and TTD should be relatively unaffected in any case: CRTO would be most at risk if cookies were restricted, but it too could manage.”

Macquarie cut its price target on Criteo to $26 from $34. Earlier this week, KeyBanc Capital Markets and SunTrust Robinson Humphrey downgraded the stock.

A report in Adweek last Friday, citing unnamed sources, said Google—which gleans a vast majority of its revenue through ads—is mulling changes to its ad tools amid heightened concern over data privacy and the threat of regulatory action. One move would be the removal of access to cookies—a way websites identify and track consumers’ preferences online—on Chrome, which could have far-reaching implications on ad revenue.

Google did not immediately respond to an email message seeking comment on the report.

Sweeping changes to how ads are presented on Chrome and Google Marketing Platform would not only impact third-party advertisers but Google itself, which had $32.6 billion in fiscal fourth-quarter advertising sales. But those are the hard choices the company faces amid withering criticism of how it, Facebook (FB), and others collect and manage personal data.

The issue has forced chief executives of both companies to testify before Congress, and it has emboldened presidential candidate Sen. Elizabeth Warren (D., Mass.) to call for the breakup of Google and Facebook.

Some tech companies have already implemented third-party tracking restrictions, such as Apple’s (AAPL) browser Safari and Mozilla’s Firefox.

Write to Jon Swartz at jon.swartz@dowjones.com