It said the companies were accused of giving financial support to the movement of US-based businessman Fethullah Gulen, who is accused of orchestrating the July 15 putsch. He denies the accusation.
None of the companies involved were named. Police began searches in the Uskudar and Umraniye districts of Istanbul, including buildings belonging to an unnamed holding company, Reuters reported.
Since the coup, more than 35,000 people have been detained, of whom 17,000 have been placed under formal arrest, and tens of thousands more suspended in a purge of Turkey's military, law-and-order, education and justice systems.