Most of us in Indian subcontinent appear in competitive bank exams and secure reputed bank jobs. Is it permissible to work in banking sector. Also some of us get employment opportunities in financial sector like insurance, stock broking, mutual funds etc. Is it permissible to work in these sectors?

Other than banks, it is not difficult. If the company is not indulging in haram matters, it is allowed. In banks, any position dealing directly with riba is not permissible.