According to the data/surveying firm Mercer, Tokyo and Osaka, Japan surpassed Moscow in 2009 as the most expensive city in the world for expats, due to a strengthening of the yen in relation to other global currencies during the economic downturn. According to Mercer's 2009 report:
Mercer's Cost of Living survey covers 143 cities across six continents and measures the comparative cost of over 200 items in each location, including housing, transport, food, clothing, household goods and entertainment. It is the world's most comprehensive cost of living survey and is used to help multinational companies and governments determine compensation allowance for their expatriate employees.
In Mercer's survey, New York is used as the base city for the index and scores 100 points, all cities are compared against New York and currency movements are measured against the US dollar. Tokyo scores 143.7 points and is nearly three times as costly as Johannesburg with an index score of 49.6.
According to the new rankings, Tokyo is the single most expensive city overall, followed by Osaka, Japan; Moscow, Russia; Geneva, Switzerland; and Hong Kong, Hong Kong.
The report measured a relatively low rate of global inflation so far during the recession, coupled with low oil prices and a general stabilization of the costs of "basic items" across the board.
Most significantly, however, is stark fluctuations in currencies towards the end of 2008 and continuing into 2009, whereby the Euro weakened significantly in relation to the dollar and the yen. According to the BBC, who reported on Mercer's findings:
Currency fluctuations as a direct result of the economic downturn had led to a "significant reshuffle" in this year's rankings, said Nathalie Constantin-Métral, a senior researcher at Mercer.
And she said that as firms looked to control costs, keeping track of the factors that dictated the cost of living for staff it sent overseas was "essential".