In futures stocks are bought in bundles.Lets say the lot size of XYZ Company is 750. If you buy one lot of XYZ Company you get 750 shares. Lets say 1 share of XYZ Company costs Rs 1,000. You have to pay Rs 7.5 Lakhs. However, you have the option to take margin. This is you pay 10% of the amount as margin money. This is 1 lot of size 100 at Rs 75,000. You can take a position just with this amount of Rs 75,000 and participate in the profits/loss.