[cbanek]

Well I think the difference is insider knowledge. If you run a public company, and know everything that is happening, that can give you a significant advantage in trading that stock.

While I agree what the President is saying can move markets, and does, it's usually not because he knows something that everyone else doesn't (non-public information). It's just that his opinion moves markets. You could say the same for short sellers, who make detailed reports and release them publicly on why they believe certain companies stock will go down. This also affects the stock price, but doesn't have any non-public information.

Now if the President was shorting all the pharmaceutical industry, then said something like "we're going to socialize healthcare", I feel like this is a bit different because it's almost like the regulator is using their information for gain. Same for congress, although funny enough, this hasn't been technically illegal for long: https://en.wikipedia.org/wiki/STOCK_Act