Earlier this week, we posted about how Saks Fifth Avenue’s shoe floor has its own zip code. But did you know that 43 buildings in Manhattan have their own exclusive zip code? Skyscrapers get their own zip codes either because of their sheer size or due to the number of people occupying them. When the original World Trade Center opened in 1973, it was also granted the privilege of a single and exclusive zip code, 10048. But the new 1 World Trade Center will share a zip code with the buildings around it (so far).

For a comprehensive list of Manhattan’s buildings with exclusive ZIP Codes, check out this graphic from Commercial Observer:

Image source: Scribd, from the Commercial Observer, September 11, 2012, illustrations by Brian Taylor

Moreover, there seems to be a trend between buildings with their own zip Codes and the amount of money they generate. According to recent analyses of tax data, people filing taxes from the Seagram Building, a building with its own exclusive zip code, have the highest average adjusted gross income of $13.9 million in the U.S.A. The studies of non-profit tax publication Tax Analysts show that out of the country’s twentieth wealthiest zip codes, eleven are from New York City, most being single buildings. This statistic certainly emphasizes Manhattan’s wealth in relation to the rest of the nation.

A number of other Manhattan skyscrapers with exclusive zip codes secured a place on the list. These include the General Motors building on Fifth Avenue coming second and the Bear Stearns office on Madison Avenue at sixth place. Their prominence emerges from containing the offices of behemoths in the business world. For instance, the Seagram Building houses offices of the private-investment firm, Quadrangle LLC and the hedge fun, Centerbridge Partners LLP.

Many of these skyscrapers have a corporate rather than residential function. Philip London, a partner at Wiss & Company LLP says there are several reasons for people using corporate mailing addresses for personal tax returns rather than home ones. Clients could be travelling frequently so it would make more sense for their financial statements to be sent to business addresses. Alternatively, they might use the address of an accountant or attorney who manages their finances.

However this may be distorting the general picture. Despite tax filers listing the addresses for their financial correspondences in such skyscrapers, that is not to say that they reside in New York or pay taxes there. As Mr. London explains, “it doesn’t give you any true indication of where wealth is.”

Other buildings with their own zip code that we have covered include the Woolworth Building and the Graybar Building.

Read more from our Cities 101 series about how stuff works in the city.