March 29 (Reuters) - Shares of Acxiom Corp plunged 27 percent on Thursday, after Facebook Inc said it would end its partnerships with several large data brokers who help advertisers target people on the social network.
The stock has now lost more than a third of its market value since Facebook's comments on Wednesday. It touched its lowest in more than 1-1/2 years in early trading on Thursday.
Facebook is under pressure to improve its handling of data after disclosing that information about 50 million Facebook users wrongly ended up in the hands of political consultancy Cambridge Analytica.
The social network has for years given advertisers the option of targeting their ads based on data collected by companies such as Acxiom. Facebook's website lists nine third-party data providers that it has worked with, including Acxiom, Experian PLC, Oracle Data Cloud, TransUnion and WPP PLC.
Arkansas-based Acxiom, which earns over $800 million a year selling consumer profiles to the world's largest companies, said late on Wednesday it did not expect this change to impact its revenue or earnings for the year ending in March.
However, for fiscal year 2019, Acxiom expects total revenue and profitability to be hurt by as much as $25 million.
Even with little raw data, third-party data providers like Acxiom attempt to build detailed pictures of individuals' finances, relationships, personal interests and purchasing tastes.
These profiles power targeted advertising across the internet, and can also be used to determine what political issues people are interested in and how they might vote.
"I welcome Facebook's announcement that it will be shutting down its partner category service, using third party data to inform targeted advertising," said Britain's Information Commissioner Elizabeth Denham in a statement on Thursday.
Shares of Acxiom were down 27 percent at $20.47 in early trading. (Reporting by Sonam Rai in Bengaluru Editing by Saumyadeb Chakrabarty)