In the past, the vast majority of those that owned their own New York City apartment lived in co-ops. For a variety of economic, regulatory and historical reasons, these types of apartment buildings dominated the world of New York City residential construction during most of the 20th century. These days, however, more and more of the residential buildings being built are condominiums.

The two types of buildings differ in some important ways. A co-op has an ownership structure closer to that of a public corporation than a typical apartment building. Instead of owning a particular apartment, like in a condominium, those that live in a co-op own a certain share in the company that owns the building. The more valuable the apartment, the larger the share of the company the resident owns.

A cooperatively owned building offers certain advantages to its residents, especially in regards to legally deciding who can move in. The guarantee of a not having an obnoxious set of neighbors moving in right next door a few years down the road has always been one of the most important benefits co-ops offer their owners.

The popularity of co-ops, however, has always been due in part to government regulations that began to be put into place during the late 19th century. Today, the ownership regulations and requirements of co-ops are simply too cumbersome for many people living in a world where people change jobs and move more often than they ever have before.

Add to this the legal changes in the regulations of Manhattan condominiums that took place in New York in 1997 that granted condo associations greater financial leeway to pay for repairs, and it's no surprise that so many of the new buildings being built in the city today are condos.

Indeed, some of the more architecturally stunning works today are condominiums. The Alexander, a twenty three story building quite close to Rockefeller center is one example of the impact that condominiums are having on the New York City skyline. The Element Condominium, at 555 West 59th, is another.

Even in these very exclusive condos, the process of purchasing a condo and subletting or selling it is usually considerably easier in comparison to a co-op. While there is an extra tax when purchasing a new condo that was not previously owned by a resident, the extra move in costs will usually be slightly less than those of an equivalent apartment in a co-op, especially if you are purchasing a condo from the previous resident.