IPO investors in 15 out of 18 central public sector enterprises (CPSEs) that listed over the last 8 years received bumper gains, as per an analysis by PTI. Mazagon Dock Shipbuilders topped the list by making investors richer by 3,700%. Rail Vikas Nigam, Garden Reach Shipbuilders and Engineers and IRCTC also provided over 1,000% returns to IPO investors.