Bull call spread is where you buy a lower call and sell a higher call. It is bullish but it is a moderately bullish strategy. In a simple call option and in a protective put position, you are very bullish on the stock or the index. But what if you are moderately bullish on the stock? You can opt for a bull call spread, wherein you buy a call option of a lower strike and sell a call option of a higher strike. So to create a bull call spread on Infosys you will buy the 600 call option at Rs.20 and sell the 640 call option at Rs.8. In this case, your maximum losses on the strategy will Rs.12 (20-8) while your maximum profit will be Rs.28 (difference of strikes less the net cost). You must use this strategy only when you are moderately bullish on the stock. In that case the premium received on the option sold reduces the cost of buying the lower option. If you use this when you are bullish then it is a waste of your view because in the bull call strategy your upside is capped.