What is the ruling on the work of a financial intermediary who executes client orders on trading screens and gives advice on buying and selling?

The work of a broker in stock trading follows the ruling of the trade itself. If the trading is unlawful, then his work is unlawful because it constitutes aiding in sin, as Allah Almighty says: "And do not cooperate in sin and aggression." But if it is lawful, then his work is lawful.