Denver (-6.9%), 2. Dallas (-3.6%), 3. Phoenix (-3.5%), 4. St. Louis (-3.4%), 5. Tampa (-3.3%), 6. Miami (-3.3%), 7. Houston (-3.0%), 8. San Diego (-0.9%), 9. Boston (-0.7%), 10. Los Angeles (-0.4%), and 11. Philadelphia (-0.3%) saw the biggest apartment rent declines, according to the 2026 Rental Housing Index by Dwellsy IQ.