At this stage I'm not quite sure I can︁ trust what DED indicated on the phone to be honest. First because it's possible the︂ guy didn't know and just provided the most logical answer (satisfaction score), secondly because only︃ official texts/decrees/rules can be used to defend yourself.
The view of the accountant you've contacted︄ is quite useful I believe. It would confirm the main source I have at this︅ stage on the topic, i.e. the commercial transaction law section 1, chapter 1, articles 4-5.︆
One document is missing for now, a decree stating that any commercial business requires a︇ commercial license (and is hence de facto regulated). It might not necessarily be a decree︈ though, since there are specific regulators. Hopefully will I find it, or can any reader︉ contribute.
In terms of instruments (the underlying behind the derivative is relevant) my first conviction,︊ based on different articles read so far, was that Forex trading absolutely requires a company︋ and a locally regulated broker: to make the activity legit - and clarify the origin︌ of funds (a highly important aspect in UAE - AML and fight against terrorism financing)︍ right away and not a posteriori. In other words, forex trading in other conditions seems︎ illegal (risks to be assessed).
Now, I'm wondering if the Forex trading case shouldn't be️ extended to any type of trading. For stocks the good news is Interactive Brokers has set up a branch in UAE/Dubai end of last year. Bad news is, if trading requires licenses, a company, locally regulated brokers/exchanges, many traders in UAE could face issues at some point. Hence the importance of working on the topic and be protected by sources/lawyers text opinions, etc...