The government will sell up to 10 per cent stake in NTPC at a floor price of Rs 168 per share through a two-day offer-for-sale ( OFS ) beginning Tuesday.The sale of 41.23 crore shares would fetch about Rs 7,000 crore to the exchequer.Shares of NTPC on Monday closed 2.48 per cent up at Rs 173.35.The two-day OFS would open for institutional investors on Tuesday and retail investors would get to bid on August 30. A retail investor is defined as the one who place bids for shares not more than Rs 2 lakh.The offer shall take place during trading hours on a separate window of the stock exchanges on T day ie August 29, 2017 commencing at 9:15 am and shall close on the same date at 3:30 p.m.Non-retail Investors who have placed their bids on T day and have chosen to carry forward their bids to T+1 day, shall be allowed to carry forward and also revise their bids on T+1 day as per the Sebi OFS circulars.