Homes in Tokyo and London have always been expensive, but the dollar's recent plunge has made these and other pricey markets particularly daunting for American expatriates, businesses and anyone unlucky enough to receive a salary in greenbacks.

That's what's happening in Hong Kong. There, in dollar-adjusted terms, a two-bedroom, unfurnished apartment runs $6,398 a month. By comparison, $4,000 a month for Moscow and $4,102 for Tokyo look cheap.

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To find these and other such markets, we used data from Mercer Human Resource Consulting, which based its numbers on 2007 data for rental properties in the Class-A market. Though it means different things in different places, a Class-A designation roughly equates to a unit in high-end, unfurnished building in a good part of town. The measures are taken at the median level, so as to exclude the ridiculous costs of premium apartments in neighborhoods like London's Belgravia or on Central Park in New York.

Rents were adjusted from local currencies to dollars. In 2007, the dollar hit a record low against the euro after falling 11 per cent in 2006. Against the pound, the dollar was at a 25-year low in 2007. Against both currencies, the greenback remains in the doldrums.

Business burden
American companies with offices in London feel an especially painful pinch. While rental prices there increased at a modest rate, when you combine subtle rate increases with the dollar's decline, you're left with a 30 per cent jump in rent from 2006 to 2007. Given that Americans can't seem to afford 3-6 per cent increases in mortgage payments, many expatriates are going to have to move into slightly cheaper digs, or perhaps consider a move to Leeds.

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But the mighty London market isn't even the fastest growing. Moscow rents have jumped by 33 per cent when adjusted for the dollar. And in a market that's still relatively cheap, such as Bangalore, India, rents have increased 87 per cent from last year. This is the result of the dollar's position against the Indian rupee and the rapid economic growth and sophistication of the Bangalore rental market, which, like the sales market, has surged along with the overall Indian economy.

This spells trouble for businesses dealing in dollars. That's because, unlike individual international buyers who are snapping up properties in New York and Los Angeles based on the cheap exchange rate, businesses don't quickly shift countries of operation based on the home currency's purchasing power. Instead, they have to absorb inflated housing costs for executives and temporarily relocate employees.

Large, multinational companies feel the pinch less than small businesses, for whom anywhere from a few hundred to a thousand a month is a lot to fret over.

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Since 2006, monthly rents in Hong Kong, as measured by Mercer, grew from $4,898 to $6,398. In Moscow, they rose $1,000, and in London they jumped about $900.

Of course, American companies that pay their overseas employees in local currencies are relatively immune. This is the case with Coca-Cola's overseas facilities, which are locally run and operated. If foreign subsidiaries are making money, the exchange rate doesn't hurt them.

"We make our money locally," says Crystal Walker, a company spokeswoman, explaining that Coke employees affected by currency swings represent "a drop in the bucket," as a small proportion of the company's 71,000 employees are based overseas.

For a company with less static international operations, like Exxon Mobil, the problems associated with currency rates can prove difficult, whether it's the yen, the dollar or the next decade's slumping currency.

"Our business is such that foreign exchange is always an issue," says spokesman Alan Jeffers. "Sometimes you win, and sometimes you lose."