The 9th U.S. Circuit Court of Appeals let stand an August 2017 preliminary injunction that required LinkedIn, a Microsoft Corp unit with more than 645 million members, to give hiQ Labs Inc access to publicly available member profiles.
She also said giving companies such as LinkedIn "Free rein" over who can use public user data risked creating "Information monopolies" that harm the public interest.
"LinkedIn has no protected property interest in the data contributed by its users, as the users retain ownership over their profiles," Berzon wrote.
In a statement, LinkedIn said it was disappointed with the decision and evaluating its options, and will "Fight to protect our members and the information they entrust" to it.
Berzon said hiQ had raised serious questions about LinkedIn's conduct, including whether it could invoke a federal law targeting computer fraud and abuse to block "Free riders" from accessing user data.
"Of course, LinkedIn could satisfy its 'free rider' concern by eliminating the public access option, albeit at a cost to the preferences of many users and, possibly, to its own bottom line," she wrote.
Donald Verrilli, a solicitor general under President Barack Obama, represented LinkedIn.