Writing under the title ‘Just how important are HMOs to the national rental housing stock?’ Propert118 has published a resume of the HMO market.

It can be seen here, and in summary says

Total HMO Value: £78 billion
Annual Rental Income: £6.3 billion
Total HMOs: 182,554

Small HMOs (3–4 tenants): 74%
Large HMOs (5+ tenants): 26%

Key Insights
London dominates in overall value and rental size, though South East HMOs command the highest per-property rent.
Smaller HMOs dominate the market (3–4 tenants), but larger HMOs still represent a significant share.
South East HMOs offer the best return in terms of average rental income.
East Midlands has the lowest per-property rent, yet its stock value outpaces lower-cost regions.
Yorkshire & Humber, while offering low values and income per HMO, still contributes meaningfully to the national rental economy.

Outlook
A COHO spokesperson notes:

“The HMO market’s value is going to keep increasing… rising tenant expectations mean landlords will improve living standards — and benefit from stronger rental returns.”
This suggests continued demand across regions, particularly where affordability and shared living appeal to young professionals, students, and migrant workers.