NEW YORK (Reuters) -Activist investor Elliott Investment Management has a large investment in data center operator Equinix and has increased its stake in the last weeks, a person familiar with the matter said on Monday, after the company's stock price tumbled last month.

The hedge fund, which has made a string of profitable technology investments including bets on Salesforce, Texas Instruments and Hewlett Packard Enterprise, has been holding discussions with Equinix, said the person, who was not permitted to discuss the private talks publicly. Neither Elliott's exact demands for the company nor the exact size of the stake could be learned.

Equinix's stock price climbed 1.5% on Monday to close trading at $789.19.

Elliott swooped in after Equinix investors were caught off guard at the company's analyst day last month by news of a higher than expected capital expenditure plan that sparked a sharp sell-off. The stock price tumbled 18% in the two trading sessions following the June 25 analysts day, the first for Equinix's new chief executive officer, Adaire Fox-Martin.

Demand for data centers is growing as AI adoption grows and analysts have said Equinix is positioned to capture some of the demand.

Bloomberg first reported the news of Elliott's investment in Equinix.