Indian Overseas Bank (IOB), posted a net profit of Rs 528.81 crore for the fourth quarter ended March 31, 2012, up from Rs 434.30 crore in the same period in the previous year. This represents a hike of 21.76 per cent. Commenting on the earnings, M Narendra, CMD, Indian Overseas Bank told NDTV Profit their net interest margins improved to 2.74 per cent versus 2.61 per cent quarter on quarter.