NEW YORK ( TheStreet) -- Activist investor Carl Icahn stepped up exposure to tech stocks during the third quarter, even as he wages multiple takeover battles, according to latest regulatory filings with the Securities and Exchange Commission.

Icahn bought Mattel ( MAT), Dynegy ( DYN), Commercial Metal ( CMC) and tech company Cadence Design ( CDNS).

He sold Anadarko Petroleum ( APC), Yahoo! ( YHOO), Micros Systems ( MCRS), Smith & Wesson ( SWHC), Ensco ( ESV), Wendy's/Arby's ( WEN) and Blockbuster ( BLOKA.A)

He added to his stakes in Motorola ( MOT), Chesapeake Energy ( CHK), Lawson Software ( LWSN), Lionsgate ( LGF), Take-Two Interactive ( TTWO) and Mentor Graphics ( MENT).

Motorola, Genzyme ( GENZ) and Biogen ( BIIB) are still among his top holdings.

>>View Carl Icahn's Portfolio

Icahn bought 9.6 million shares in energy company Dynegy during the third quarter as part of his efforts to oppose Blackstone's ( BX) $4.50 a share takeover bid, which he has argued is too low. Most recently, he offered a $2 billion credit line to Dynegy to allay fears that it may face a liquidity crisis should the takeover bid fail and urged shareholders to vote against acceptance of the deal. Both Dynegy and Blackstone have vehemently opposed Icahn's arguments ahead of a crucial shareholder vote on Nov. 18.

Icahn has also launched a takeover bid for Lionsgate while attempting to orchestrate a buyout of MGM Studios by the former in the process. MGM recently filed for bankruptcy and Lionsgate is still said to be in talks with Icahn regarding the takeover. .

Investors managing over $100 million assets are required to report their holdings every quarter in a 13F filing within 45 days from the end of the quarter. The managers do not need to disclose short positions or investments in non-U.S. listed securities.

--Written by Shanthi Venkataraman in New York

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