It is possible that this is a private file, a very recent upload from a niche Analog Horror series, or a reference to a specific bank transaction or data file. However, if you are looking for a "deep post" analysis, it might be related to one of these similar sounding mysteries:
The name follows a format often seen in "Lost Media" or "Creepypasta" stories where a user finds a corrupted file on a used hard drive. BANK-105.mp4
In certain video game lore (like SCP Foundation or Roblox horror games), files are often named with prefixes like BANK followed by a number. It is possible that this is a private