As long as you are in Belgium at the time of your subscription (given that Spreds only does marketing in Belgium), you can invest if you pay taxes in one of the following countries.

 
Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, and Sweden.

 
Iceland, Lichtenstein, Norway, and Switzerland.

 
Andorra, Lichtenstein, Malta, Monaco, San Marino, and the Vatican.