100-Hour Test
You participate more than 100 hours in the activity, and no one else β including a cleaner, co-host, or property manager β participates more than you.
Multiple STR properties may sometimes be combined into one activity for this test, if they qualify as an "appropriate economic unit" under IRS facts-and-circumstances rules. This isn't automatic β eligibility depends on ownership, property type, and management overlap.
Treas. Reg. Β§1.469-5T(a)(3); grouping under Β§1.469-4
500-Hour Safe Harbor
You participate more than 500 hours in the activity. No comparison to anyone else is required.
Treas. Reg. Β§1.469-5T(a)(1)
This is general information, not tax advice. Talk to your CPA before relying on either test.