What Is an Investment Analysis API, and Why Every PropTech Needs One Single-family rental cap rates climbed to 7.3% by the end of 2025, nearly two full percentage points higher than they were back in 2021. That’s the kind of shift that quietly breaks every underwriting model still running on last year’s comps. If your platform calculates cap rate, cash-on-cash return, or occupancy by pulling numbers from a static spreadsheet someone built during onboarding, those numbers are already stale.