Introduction to Open Interest
Volume & Open Interest are the most important parameters for judging the Futures & Options market. Volume can simply be defined as the number of contracts traded on a particular day. Open Interest is slightly more complex data.”
The Open Interest figure for a given future/option is the number of contracts outstanding at any given point of time. The Open Interest increases when trader “A” opens a new position by buying a future/option contract from trader “B” who did not previously hold any position in that future/option contract (“B” will said to be holding a "Short Position" in the future/option contract). When trader “A” closes out the position by selling the future/option contract, the Openinterest would either remain the same or go down. In brief Open Interest is the total number of future/option contracts that are not closed or delivered on a particular day.
Example
Monday Client A buys 2 futures contract of Reliance and open interest
Client B sells 2 futures contract of Reliance. 2
Tuesday Client C buys 10 futures contracts of Reliance and
Client D sells 10 futures contracts of Reliance. 12
Wednesday Client A sells 1 futures contract of Reliance and
Client D buys 1 futures contract of Reliance . 11
Thursday Client E buys 7 futures contracts of Reliance and
Client C sells 7 futures contracts of Reliance. 11
On Monday Client A and Client B create 2 contracts that are left open this brings the open interest to 2 contracts.
On Tuesday Client C and Client D create 10 more contracts that are left open this brings the total open interest to12 contracts
On Wednesday Client A and client D take an offsetting position and therefore open interest is reduced by 1.
On Thursday, Client E simply replaces Client C and therefore open interest does not change
Increasing OI with increase in price trend (Long build up) is considered positive –
With increase in OI and the market price, the trend shows bullishness on the back of addition of more long positions in the futures market. Investors are turning positive and going long for the stock, which is evident by the upward price movement
Increasing OI with decrease in price trend (Short build up) is considered negative –
With increase in OI and fall in the market price the trend shows bearishness on the back of addition of more short
positions in the futures market. Investors are turning negative and price is falling with selling pressure coming due to increasing negativity in the specific stock
Decreasing OI with increase in price trend (Short covering) is considered positive –
With decrease in OI and rise in the market price the trend shows bullishness on the back of covering up of short
positions in the futures market. With the short covering happening due to investors getting caught on wrong foot the price escalates well over the normal levels
Decreasing OI with decrease in price trend (Long Unwinding) is considered negative –
With decrease in OI and fall in the market price the trend shows bearishness on the back of closing up of long position in the futures market. Investors booking profits creates selling pressure and thus shows the bearish trend prevalent in the market.