The Knight Frank Global Cities 2015 Report shows which cities are the most expensive in terms of commercial real-estate.

The Skyscraper Index sees London ranked the highest in terms of rent in Europe, with space costing US$2,400 per sq ft. It comes fourth out of the the ten most-expensive cities in the world.

1. Hong Kong US$6,330

2. Tokyo US$4,180

3. New York US$2,980

4. London US$2,400

5. San Francisco US$2,260

6. Singapore US$2,000

7. Sydney US$1,740

8. Shanghai US$1,670

9. Beijing US$1,600

10. Los Angeles US$1,230

Why is Hong Kong number one? Knight Frank says is it is because of three key factors:

  1. A restricted geographic area, which means building upwards, effectively converting air into land.
  2. Volatile office rents mean investors can potentially reap high rewards in the long-term.
  3. The “ego” appeal of the upper floors, with the panoramic views, delivers higher rents compared to the wider market.