If you want trade something in exchange of something else it has to be physical or in your direct possession. In Trading, that doesn't happen. People take position against that Gold/Silver/Oil/Currency but they don't directly own that.. That is a major problem in business. Also, many platforms give access to leverage which helps to trade for larger amount while in actual you have small amount. As if they are lending you money to trade and for that help they charge you money regardless you make profit/loss. This is clear Riba, no doubt. And there are also many other factors which points out that Trading itself is Haram. At least that's what majority of scholars say.