Those who are better suited to this can make sales instantly or near instantly (talking about C level and up in INT and Trading). If your INT or Trading skill is lower than C level, your sales are entered into the term but don't actually happen until after a period of time passes. The further you are from C level the worse the delay is.
This means that while everyone can see all the details on ticker and/or can get inside scoops and advance warnings via other means, the higher your INT and Trading the faster you can react to the data. While this would disadvantage those with lower INT or Trading, it is not enough to mean that higher stat/skill always winds.
I would also suggest that the lower of your INT or Trading is considered for determining how much delay your sales will suffer and that the actual delay is a random value within a range that is more and more favorable the higher your INT and Trading is.
With something like this in place, Bob and Sue might both see that NK stock (which they both heavily invested in) is tanking at the same time but Bob (who has higher INT and Trading) will manage to sell off his stocks than Sue can and thus secure greater profit or avoid greater loss.
Also, I only suggested delayed sales because applying it to both would double the impact a change like this would have (possible to an undesirable degree). Also, I suspect that buying shares would be easier than selling (but I am not stock market expert IRL).