It was obviously Drugs, Alcohol or Suicide. Why else would it be so hush hush. If he had a heart attack or if he died of natural causes I would think they would mention it. The fact that they are so unwilling to say leads me to believe it was something that would make CNBC look bad or Hurt Marks Family and legacy. I really liked him, he was honest, he always asked the tough questions and seemed to want to get the truth out about the Failing economy and the coming economic Depression. R.I.P.