As a Muslim, you can speculate with any type of investment account if you do it wisely. Paying interest is haram. When you speculate on, for example, stocks or currencies with derivatives, you pay interest if you hold the position open for more than one day. Day traders close their position before the end of the day. Day traders speculate on rising and falling prices. By closing your positions in time as an active investor, you can therefore actively trade halal.