NATO (National Association of Theatre Owners) is currently trying to shorten the length of movie trailers, according to a released guidelines document. The association says, "These guidelines will evolve in response to technological innovations, marketing and advertising trends, competition in the marketplace, and consumer demands".

They would like to see trailers to be released no sooner than 150 days before a film is released, and other in-theatre marketing limited to 120 days out, as well as trailers being given a limit of no longer than 3 minutes.  Other guidelines "will only place trailers with content appropriate for the particular feature", in accordance with guidelines set by the MPAA.    

The new guidelines will apply to films released on or after October 1.