Nov 8 (Reuters) - Elliott Management Corp has taken a stake in software firm F5 Networks Inc, making it one of the company's largest investors, a person familiar with the matter told Reuters.

The size of the position was unclear, but it fell below the 5% threshold that would require regulatory disclosure. The news was first reported https://www.wsj.com/articles/elliott-management-takes-stake-in-software-company-f5-networks-11604870484 by The Wall Street Journal on Sunday.

The activist-investor spoke to F5 Networks' management in recent weeks regarding ways to boost its lagging stock, the newspaper said. The report added that Elliott managers questioned the software company's recent acquisitions of Shape Security Inc and Nginx Software Inc, suggesting it may have overpaid without a clear integration strategy.

F5 Networks bought Shape Security last year for a total enterprise value of about $1 billion in cash and acquired Nginx Software for about $670 million.

F5 Networks did not respond to Reuters' request for comment.

Founded in 1977, New York-based Elliott managed approximately $41 billion in assets, as of July 1, making it one of the largest and oldest hedge fund firms in the world. Still led by billionaire founder Paul Singer, the multi-strategy firm has developed a formidable corporate activism unit led by Jesse Cohn.

(Reporting by Maria Ponnezhath in Bengaluru and Lawrence Delevingne in Boston; Editing by Peter Cooney, Lincoln Feast and Sherry Jacob-Phillips)