New York City has one of the most expensive real estate markets in the world, a distinction earned via a boost from wealthy foreigners snapping up pricey apartments.

The Big Apple is second only to London in its popularity among foreign investors, according to a survey in January by the Association of Foreign Investors in Real Estate. While there isn't one specific group making all the purchases, real estate professionals tell CNBC they've detected certain trends in key neighborhoods across the region, with buyers from Europe, Asia and the Middle East all in search of a solid investment.

One of the key groups is Chinese buyers. When China's economy showed signs of slowing a few years ago, evidence suggested that wealthy nationals were snapping up U.S. assets in order to get money out, an effect that has yet to abate even as Chinese buying slows in other parts of the country.

"Chinese clients have been buying $5 million-plus condos on Fifth Avenue and Park Avenue, $1 million to $2 million condos on the Upper West Side, and $2 million to $5 million condos in Tribeca and SoHo," said Carole Armstrong, a real estate agent with DJK Residential, citing some of the city's ritziest areas.

Separately, buyers from Russia and the Middle East are snapping up properties in luxury hotbeds such as Columbus Circle and Central Park West, Armstrong added.



"Russians are particularly interested in the name and cachet of the building," said Rena Kliot, founder and CEO of Pulse International Realty. "When there is a certain 'wow' factor and luxurious reputation or square footage like full-floor units or history associated with the property, they're interested."



CNBC spoke with several real estate professionals about which neighborhoods are the most popular with foreign nationals, and why.