An annual rise of 2.1% in the 12 months to September represents the index's weakest rate of annual growth for almost five years.

Dubai holds the top spot for the second consecutive quarter, recording a 12.4% increase year-on-year. However, the rate of rental growth in the Emirate is slowing with no change recorded in prime rents in the three months to the end of September.

Prime rents in both Tokyo and New York accelerated over the 12 month-period, by 9.8% and 7.9% respectively. Japan, having voted this week for a second term of Abenomics, may – if Prime Minister Abe’s monetary stimulus measures prove successful – start to be the target of more multinational relocations boosting prime rents further.

The index’s overall slowdown becomes apparent when the results are compared year-on-year. In the year to September 2013 nearly 90% of the cities tracked saw prime rents increase on an annual basis; this figure has now shrunk to 66%.

Luxury rental demand is firmly linked to demand from corporate tenants and hence business sentiment. With the global economy stuttering in 2014 business sentiment has dipped, indeed Markit’s Global Business Outlook Survey is now at a five-year low.

Concerns over a renewed downturn in the Eurozone, a potential interest rate hike in the US and the UK as well as tension in Ukraine and the Middle East are weighing on economic confidence.

Prime rental markets often move in the opposite direction to the sales sector. With the luxury sales market now the target of both cooling measures (Asia) and a changing tax landscape (UK, US, France) we expect the Prime Global Rental Index to strengthen in 2015 with London and New York leading the way.