The announcement was made about three months after Blum's "Insidious" was released. That movie, a FilmDistrict release, was made for about $1.5 million. It has grossed $80.7 million worldwide since April 1.
Paramount, which released both "Paranormal" movies, has set a release date of Oct. 21 for the third.
Blum has produced more than 20 movies, including "The Amityville Horror: The Lost Tapes" for Dimension Films and "The Boy," for Lionsgate.
He opened Blumhouse in 2000.