How Trump Could Make A Mint Off The White House

If the presumptive Republican nominee Donald Trump wins the presidency this November, it will be a historic result for many reasons. In addition to being the first self-proclaimed billionaire and the oldest first-term president elected, he could also be the first president of the modern era to use the office to make money for his companies and himself.

Every employee of the executive branch is required by law to avoid taking part in decisions that might directly affect their economic interests. But these laws do not apply to the president or the vice president. In practice, previous presidents have followed those rules anyway, putting their major holdings in blind trusts to avoid any real or perceived conflict of interest.
http://thinkprogress.org/politics/2016/06/14/3785467/trump-conflicts-of-interest/