** India's Vishal Mega Mart VSSL.NS sheds 5.5% to 117.98 rupees
** Top shareholder Samayat Services to sell stake worth 50.57 bln rupees ($588.6 mln) in VSSL via block deals, CNBC-TV18 reports
** Stake sale at floor price of 110 rupees apiece, a 12% discount to co's closing price on Monday
** Samayat, which holds 74.55% stake in VSSL, will offload 10% of its holding via the share sale- report
** VSSL and Samayat did not immediately respond to Reuters requests for comment
** Stock trims YTD gains to ~11%
($1 = 85.9100 Indian rupees)
(Reporting by Kashish Tandon in Bengaluru)
((Kashish.tandon@thomsonreuters.com))