Donald Trump’s business, The Trump Organization, is in violation of New York City law, NBC News has learned. The Trump Tower skyscraper located at 725 Fifth Avenue -- where President Trump and Melania live in the penthouse apartment and his two eldest sons work in offices just below -- is not registered this year with the New York City Department of Housing Preservation & Development, a spokeswoman for the department confirmed on Tuesday.

Property owners of certain residential buildings are required by law to register annually by Sept. 1, but Trump Tower’s registration expired in 2016 and The Trump Organization did not renew it until today. Failing to register can result in a fine of up to $500, and revokes some of the rights usually enjoyed by property owners.

The Trump Organization has a $100 million mortgage on Trump Tower. The loan was written by Wall Street firm Ladder Capital Financial and it now resides in a trust and has been securitized.

Calls and messages to a spokeswoman for The Trump Organization were not immediately returned.