The first rule of working with a billionaire buyer is: You do not talk about the billionaire buyer

Michael Dell may have bought his $100.5 million penthouse at One57 years ago, but a strategy that included multiple nondisclosure agreements and pass-through entities allowed him to keep his identity a secret until last week.

Dell — who was represented by the Corcoran Group’s Leighton Candler in the sale — relied on a close network of agents, architects and others to keep his record-setting purchase a secret, a sign of how much value the country’s top earners have started to place on privacy when it comes to their real estate dealings, according to the Wall Street Journal.

“People don’t want people knowing what they spend,” Douglas Elliman broker Frances Katzen told the Wall Street Journal. “You almost have to channel the purchase through three different subsidiaries to hide the buyer, and most prefer to have some kind of gag order in place with the people they’re working with.”

The chief executive of Dell bought his condominium through the limited liability company, P89-90, and his attorney Andrea Riina signed every document related to the sale. He also does not seem to have taken out a mortgage on the building, further limiting the number of public documents. However, a permit filed with the city’s Department of Buildings does have Dell’s name on it, but only says that he is renovating the condo and wants to take out its sauna to make room for more storage space. [WSJ] – Eddie Small