Tata Chemicals said on Wednesday it has posted a net profit of Rs 138.5 crore on consolidated basis in the fourth quarter ended March 31, marginally down from Rs 145.83 crore reported in the same period last year. But the company reported a 28 per cent increase in net profit after minority interest at Rs 838 crore for the year ended March 31, against Rs 653 crore in the corresponding period last year. Meanwhile, Tata Sons deputy chairman Cyrus Mistry was appointed on its board of directors.