Is it permissible to work as an IT engineer at Fidelity Investments?

If the new field of work does not directly involve forbidden acts or aiding therein, then there is no harm in transitioning to it. A Muslim must strive for what is lawful and avoid what is forbidden and doubtful, for whoever avoids doubtful matters has acquitted himself regarding his religion and honor. And whoever gives up something for the sake of Allah, Allah will compensate him with something better and provide for him from whence he does not expect.