Dear, greetings of the day...
please check this pic...
if i buy the tatasteel options, with strick price 580. at the time of buying underlying is trading @568 and now the buy price of option is 3.50
if tatasteel keep on growing....how can i calcutate my profit. if the pirce dropes, at what stage starts my loosing.
as of my knowledge...until it reach(the price of tatasteel) 580 there is no profit for me.after 580, how can i calculate.
please, explain this.
Swamy, what you are asking is fundamental question of option pricing, and how the price change as the price of underlying changes.
That is a big topic and I will not be able to do justice in this reply... So please read about option pricing at sources that I have given in one of the first few post)
In short, option price at any stage has two part - Real Value and Time value. Real Value of Call is strike price - spot price. Ofcourse, this real value shd be +ive number. Time value, is anything that u pay above real value.
So when spot is at 568, 580 CALL has no real value. it is OTM. So whatever u pay i.e. 3.5 is time value. (infact, the price is not 3.5, but 3.75. Cause when u go to buy this option, next seller is asking for 3.75 to sell.. so plz look at right column for price. In low value stock option, it makes lot of difference. by paying 25 paise more on 3.5, u are already 8% behind in the game).
This TVal represents the probability of market reaching above the strik price + premium ie.. 3.5 for 580 call represents the chances of stock reaching above 583.5.
This probability depends on where the spot is now. and how many days are remaining before option expiry.
So if stock at 568, then it has to travel 16 rs in next 20 trading days..
a) With each passing day, assuming stock remains at 568, this probability will start dropping and hence the premium will also start falling.
b) If stocks moves to 572, tomorrow, then in next 19 days, it has to travel 12 rs.. hence probability of this happening is higher then 16rs in 20 days. So the premium will go up.
So though the stock has not reached 580, but the premium will increase tomorrow and you will see profit.
In reality, part (a) and (b) work simultaneously. That makes a bit complicated to know the price change in option. Better to use some option pricing calculator/ excel sheet/ tool
for this purpose.
Tricky part is if not many days left, then even if stock moves up, your call premium may fall. Cause 1 days has passed and in remaining days, it is less probable that option will be able to give profit
to the option buyer. So why would they pay 3.5 then. They might just pay 1 rs when there are 5 days left and still stock is around 575.
Hope this give u some idea about option pricing. Plz read more on this.
Happy Trading.