O.C. BUSINESS PLUS : ORANGE COUNTY BRIEFLY : TDK Acquires Large Stake in Irvine’s Vertex Networks

TDK Corp., the world’s largest maker of audio and video tapes, said it has acquired more than a fourth of privately held Vertex Networks Inc., an Irvine-based semiconductor company, for $25 million in cash.

The purchase makes Tustin-based TDK Semiconductor Corp., a wholly owned unit of TDK, the largest shareholder of Vertex, said spokesman Nobuyuki Koike.

Vertex, which has 50 employees and annual sales of $14 million, makes advanced integrated circuits known as controller ICs. TDK will send a team of researchers to the U.S. company, Koike said. The Japanese company plans to retain Vertex’s workers.