There is a difference between being late to a deadline and being ineligible for it. Several of the rooms most worth pitching in have a moving image requirement written into the submission form, in exact minute counts. No trailer, no application. Not a weaker application. No application.
I think this is the single most useful thing I know that nobody seems to say out loud, so here it is with the wording copied straight off the forms.
Trailer or teaser of max. 3 minutes long (link to online viewing with English subtitles). CPH:DOX / CPH:FORUM submission requirements
Not encouraged. Not recommended. It is on the list of what you submit. Submissions typically open in early September and close in early November, which is why the work gets bought in August.
Early stage: 2 to 3 minutes of footage or visual material (teaser, test footage; does not need to be polished). Advanced: 4 to 5 minutes. DOC NYC Pitch Day submission requirements
Read that parenthesis carefully, because it is the most generous sentence any of these bodies has written: it does not need to be polished. They are telling you the bar is lower than you think. What they will not accept is nothing.
3 minute preview: trailer, teaser, or scene selection, no longer than 3 minutes. Sheffield DocFest MeetMarket submission requirements
Note "scene selection." A well-chosen run of scenes counts. You are not always being asked for a cut trailer, you are being asked for evidence that a camera has been pointed at this thing.
If available, a trailer or scene selects are encouraged. Hot Docs Forum submission requirements
Conditional at the Forum, required for Rough Cut. And to correct something I hear repeated: Hot Docs is not dead. It lost a lot of staff in 2024 and paused the 2025 Forum, but the 2026 Forum ran and paid out $48,000. Writing it off in front of anyone who was in that room will cost you.
Visual material is recommended (trailer or equivalent). IDFA Forum submission requirements
The softest of the five. "Recommended" in a room this competitive means everyone else brought one.
Work the deadlines backwards and the year has a shape. The autumn markets close between roughly early November and the end of the year, and a sizzle takes three to six weeks if the material exists and longer if it does not. That puts commissioning in August and September for a market you are pitching in the autumn.
Which means the useful question is never "should I make a trailer." It is "which room am I walking into, and when does its form close." Answer that and the rest is arithmetic.
My favourite piece of evidence that this is now standard is not a market at all. Pacific Islanders in Communications shut down its research and development fund, and now points development-stage filmmakers at its Shorts Fund to create, in their words:
a proof of concept for a full length film. Pacific Islanders in Communications, Media Fund
An institutional funder, in writing, telling filmmakers to go make a sizzle. When the money itself starts saying it, the argument is over.