MEXICO CITY - Top Mexican drug lord Joaquin "El Chapo" Guzman has dropped off Forbes magazine's billionaires' list after four years on it.

Guzman is the fugitive leader of the Sinaloa drug cartel. He first made the list in 2009, with a fortune listed at about $1 billion.

Forbes senior wealth editor Luisa Kroll said the decision to drop Guzman was based on suspicions that "an increasing chunk of money is going to protect him and his family."

Kroll said in a statement Monday that Guzman is "no longer someone we are confident enough to call a billionaire," and that he could not be reached to verify figures on his wealth.

Mexican telecom magnate Carlos Slim continues to head the list, with a fortune estimated at $73 billion.