The thing is – if you have such an incentive and you are faced with the choice between reporting a boring truth or a spiced up lie, you will go for the later. And that has nothing to do with journalism anymore.
It _could_ work – if the editors are espeically on the hunt for bogus stories.
The reason trading on stocks they cover is bad is that it creates an incentive to create news that may not be true to move the market, thus indirectly rewarding them with financial benefit.
The policy of rewarding them for moving the market simply removes the intervening steps and directly rewards them.
In concept, this only makes it worse. How much worse depends on how compensated they are, which I don't know. (e.g., if the bonus is $50 and your boss buys you a latte the next morning, it's not really that big a deal, vs. if it's $25,000 and everyone knows it's a fast track to promotions it's a pretty significant problem)
I can see how it incentivises sensationalism though. I was a tech magazine editor. I did my utmost to check the veracity of stories. I would have hated to think that my journalists were being incentivised to exaggerate.
Did you know that?
(https://www.businessinsider.com/bloomberg-reporters-compensa...)