While there are a number of reasons that you might want to purchase an apartment as a Limited Liability Corporation (LLC)—such as privacy, asset protection, and as a safeguard against liability claims—be prepared to jump through a few extra hoops with your potential new building in order to do so—especially if it's a co-op, says Steven Wagner, a co-op and condo attorney with Wagner Berkow LLP and a longtime board member of his own 420-unit Manhattan co-op.

Most condo buildings make the process relatively simple.

"Unless there's some prohibition against LLC buyers in the bylaws of the condominium—and I don't believe I've ever seen any—you can just go ahead and buy," says Wagner. "Unlike a co-op, a condo can't say yes or no to your purchase, all they can do is exercise the board's right of first refusal, which very few buildings do."

With a co-op, however, there are more potential problems to head off, and you'll want to find out about a particular building's policies before moving forward.

For starters, says Wagner, there used to be a section of the Internal Revenue Code that required buyers of co-ops to be individuals, and not an entity like an LLC or a trust. Though the law was changed many years ago, you'll find that some older buildings never bothered to change the language of their governing documents, meaning that the rules still technically prohibit a purchase by an LLC.