Definition
A promotional-release effect is a short-lived market reaction to a scheduled marketing disclosure -- a product reveal, a preview, a teaser -- that generates a temporary spike in public attention and speculative activity, typically decaying faster than the reaction to the underlying event's actual release.
In Panel Profits
'Trailer-Drop Catalyst' is Panel Profits' own name for the specific attention spike generated when a first trailer or teaser for a comic-derived film or show is released, as distinct from the earlier Casting-Announcement Catalyst (earlier in the production timeline) or a Streaming-Premiere Catalyst (at actual release). It is the platform's own subdivision of its broader Asset Catalyst concept into the promotional-timeline stage at which the reaction occurs; it is not an externally used market term.
Comic-market example
A trailer that visually confirms a previously-unconfirmed comic-accurate costume or character detail for a key first-appearance issue tends to produce a sharper, more targeted trailer-drop reaction than the earlier, more speculative casting announcement did.
Common mistakes
Do not assume a trailer-drop catalyst's reaction magnitude will simply add on top of the casting-announcement catalyst's -- a trailer that contradicts or underwhelms relative to what the casting announcement implied can just as easily produce a cooling reaction instead.