New Delhi, July 25 -- Retail appetite for shares of National Securities Depository Ltd in the unlisted market over the past year was met in a significant way byHDFC Bank Ltd, one of the top six selling shareholders in NSDL's Rs.4,011.6 crore initial public offering. The IPO, a pure offer for sale, will open on 30 July.

HDFC Bank was the only significant shareholder that pared its stake in NSDL by 1.99 million shares, or a percentage point, to 7.95% over a year through 23 July, when the depository filed its offer documents with the Securities and Exchange Board of India.

Returns for HDFC Bank at the upper end of NSDL's Rs.760-800 offer band would be 702%, or Rs.161 crore, as its weighted average cost of acquiring NSDL shares was Rs.108.2...