answer can given by to style, one is bookish answer, n second is hidden messages in it.
1) today call options been mostly traded, most guys buy calls and most guys sell calls compare to put option.
2) to complete a trade there need to be a buyer for every seller, so if one has to buy a call then one has to sell that call, selling calls need more margin and buying call need less margin, so option sellers r smart crowd ( its just loose consideration, though things vary as per personal style), also one buy call to hedge his/her short nifty,here more margin requires to do that as well, so this type of buyer is also considered to be a smart money, all in all when open interest in call option increases its bearish, suggests smart money expecting market may go down.
Hope this helps as its not a 2 para concept one need to go deep to study everything.This is the best way i can clarify.
1) today call options been mostly traded, most guys buy calls and most guys sell calls compare to put option.
2) to complete a trade there need to be a buyer for every seller, so if one has to buy a call then one has to sell that call, selling calls need more margin and buying call need less margin, so option sellers r smart crowd ( its just loose consideration, though things vary as per personal style), also one buy call to hedge his/her short nifty,here more margin requires to do that as well, so this type of buyer is also considered to be a smart money, all in all when open interest in call option increases its bearish, suggests smart money expecting market may go down.
Hope this helps as its not a 2 para concept one need to go deep to study everything.This is the best way i can clarify.
today nifty broke some key levels which were crucial for further uptrend. After those levels broke, put writers (who were bullish & expecting further upmove) had to exit their positions (leading to reduction in OI of puts), and instead 3100+ calls were written, as after closing below 3000, these levels would be tough to break again soon & easily
By the way, check out today's top traded nifty options:
3200 Call & 3000 Put