Final answer:
FINRA considers vacation homes to be "non-branch" locations if they are used temporarily for business, with the condition that such use falls under a certain number of days per year according to FINRA regulations.
Step-by-step explanation:
The Financial Industry Regulatory Authority (FINRA) categorizes vacation homes as "non-branch" locations provided they are utilized for securities business purposes on a temporary basis. These vacation homes do not require registration as a branch office as long as their usage does not exceed a specific number of days per year. The exact number of days is determined by FINRA regulations which may be updated periodically, hence it is crucial to refer to the latest FINRA rules or consult with a compliance expert for the current threshold.