A six-year-old suit brought by investors in a slate of movies produced by Paramount Pictures has been greenlighted for trial, which opens on Oct. 20.

The investors, headed by the Allianz insurance company, allocated $40 million to 25 films released between 2004 and 2006. Among films in the slate known as Melrose 1 are “Elizabethtown” and “Mean Girls.”

The investors lost their entire pool because, they allege, Paramount abandoned its historic practice of foreign pre-selling, or selling abroad to reduce the risk with substantial up-front payments from overseas entities.

Paramount, which claims not to have changed its pre-selling strategy, filed for summary judgment in May. That motion was denied Tuesday by Manhattan federal Judge Thomas Griesa.