What is Open Interest?

  •  4 min read
  • 0
  • 01 Dec 2023
What is Open Interest

Key Highlights

  • The total number of active contracts that are not yet closed or resolved is known as open interest.

  • The open interest will rise when a new buyer and seller sign a contract. It will decline if contracts are closed or executed. But open interest doesn't change when a new buyer and an old seller sign a contract.

  • The open interest to volume ratio shows that open interest and volume are not the same. Open interest is a running tally of the active contracts. Whereas, volume is the total number of contracts exchanged in a given time frame.

  • To gain a deeper understanding of money movement in the stock market, traders and investors can utilise open interest along with other indicators such as price and trading volume.

"Open interest" refers to the total number of open contracts market participants hold after a day. It can also be referred to as the overall number of futures or option contracts that still need to be executed, expired, or completed by delivery.

In particular, open interest applies to the futures market. Open interest, or the total number of open contracts on the security, is often used to confirm trend reversals in futures and options contracts. Money flows into the futures market are measured as "open interest." There must be a buyer of that contract for each seller of a futures contract. Thus, only one contract is created by the seller and buyer.

Therefore, we need only know the totals from one side or the other, buyers or sellers, not the sum of both, to determine the total open interest in any given market. The number of contracts on a day shall be shown as an increase or decrease in the Open Interest position, which is notified each day and will be presented positively or negatively.

Open interest is calculated for a specific derivative contract by summing up the total number of long and short buy and sell contracts. There are long-side buyers and short-side sellers in every futures or options contract. Open interest will increase when a new contract is entered into between the purchaser and the seller. Open interest shall be reduced by one when an existing contract is replaced by the seller's and buyer's closing of positions.

There are some key principles to use the open interest. The following table illustrates them.

Price Volume Open Interest Market

Technical experts believe that the trend will continue as long as there is a high level of bullish sentiment and more traders are opening new contracts the open interest will rise. Technical analysts conclude that a trend is waning when the price rises and open interest falls. A declining open interest is a sign that traders are getting rid of their positions. Technical analysts deduce that a trend is weak when the price falls and the open interest value rises. Traders usually think that the particular trend is strengthening and will reverse when the price and open interest decline.

Open interest is used to estimate the amount of money coming into or going out of a futures or options market is estimated by. A rise in open interest indicates fresh money entering the market. Whereas, a fall in open interest indicates money leaving the market. It provides information on an option's liquidity. So, it is very crucial for options traders.

Consider an example of calculating open interest on futures contracts, the common area where open interest can be applied.

Example: Suppose you follow a futures contract for "XYZ" in the stock market. There are 100 shares of Stock XYZ for each futures contract.

Let us calculate the open interest for each day:

Day 1:

  • The purchase of Trader A increases open interest by 5 contracts.
  • 3 contracts have been taken off the Open Interest by Trader B's sale.
  • Open interest on Day 1 is (5 - 3) = 2 contracts.

Day 2:

  • The purchase of trader C has resulted in 2 contracts being opened for interest.
  • The sale by trader A results in a reduction of 1 contract's outstanding interest.
  • Open interest on Day 2 is (2 - 1) = 1 contract.

Day 3:

  • 4 open interest contracts are added to Trader D's purchase.
  • Open interest is multiplied by 2 contracts when trader B buys to cover his short position.
  • Open interest on Day 3 is (4 + 2) = 6 contracts.

So, the open interest for the Stock XYZ futures contract is 2 contracts on Day 1, 1 on Day 2, and 6 on Day 3. An open interest is helpful for understanding the level of liquidity on the market. Greater open interest will make it easier to trade and exit at competitive bidding or asking rates, because the market is more liquid.

In the futures market, open interest and volume are the two key ideas. Investors use both these indicators to forecast trends. They are some common aspects. However, OI and volume are not the same.

Open interest indicates the quantity of open contracts held by individual buyers and sellers in the futures market. In this market, a buyer should exist for each contract that is sold. Thus, the total number of contracts that are transacted during the day stays balanced. Volume is the total number of contracts that are completed in a given day. Thus, if one contract is purchased and sold, the volume increases by one.

The volume is set at zero when the day starts. As a result, you are able to see exactly how many contracts are traded during trading hours. Compared to volume, open interest is more easily visible. Depending on how many traders enter or leave the deal, the open interest value may or may not change.

Let's use an example to understand this better. Assume that A, B, and C are the three traders present in the market. Buyer A purchases all the 10 futures contracts that Seller B sells on the first day. Thus, following the first day, open interest and volume were both 10.

The next day, C purchases 7 contracts and A sells 7. When the second day ends, the volume changes to 7 (the number of contracts that were exchanged). However, open interest stays at 10 since the market did not produce any new contracts.

It is vital to remember that open interest may fluctuate for days,. Whereas, volume varies every day. Until new contracts are started or the existing ones are settled or executed, open interest will stay the same.

Open interest is used to measure market activity. There are no openings, or nearly all positions are closed because of little or no open interest. High open interest means several contracts remain negotiated, and market participants will pay close attention to these markets.

Open interest refers to money flowing into or out of a futures or options market. Open interest refers to new or additional money that comes into the market, while lower open interest indicates outflows from the market. Open interest is essential to options traders as it provides vital information on option liquidity.

Open interest has several benefits. You can monitor and know different changes in the stock market. Evaluate Open interest to gain & take different advantages which are as follows:

  1. New funds flow to the market as open interest increases. This will lead to the continuation of the current upward, downward, or sideways trend.

  2. The decrease in open interest shows the market's decline and indicates that the price trend has ended. In particular, open-interest knowledge can be helpful in reaching the end of significant market movements.

  3. After a prolonged price gain, a leveling off of open interest is frequently a sign that an uptrend or bull market is ending.


Open interest is the total number of open derivative contracts that have not yet been settled. They are still not used, finished, or run out. This measure is linked to the options and futures markets rather than the stock market. Instead of adding up all of the transactions between buyers and sellers, open interest is based on the total number of open contracts. Open interest is typically not used as a trend or price movement indicator. If you plan to keep taking steps into futures and options trading, go ahead with the Kotak Securities app and get tons of tools & insight on stock market trading.

FAQs on Open Interest in Share Market

Open interest is a measure of market participation. An increasing open interest indicates additional money is coming in to the market which suggests that the trend is strong. Conversely, a decreasing open interest may signal that the market sentiment is becoming weak.

Highest open interest is often observed at a specific strike price. This strike price is termed as the "max pain" point. It represents the level where an option writer would have lowest possible losses.

The market weakens if prices rise, volumes fall, and Open Interest declines. However, if prices fall and volumes and open interest rise, the market is weak; if prices fall and open interest fall, the market gains strength.

The greater the open interest and the volume, the better the liquidity and the more efficient the pricing. The trading volume shall be set daily, and the opening interest shall remain constant for the duration of the option.

Generally speaking, when the open interest in calls is higher than the open interest in puts, there is a higher bullish trend in the market.

Open interest is essential for intraday traders because it can indicate the level of interest in a particular security. The high level of open interest indicates that many traders are concerned about the security, which could cause more volatility and price movements.

In case of zero open interest there will be no contracts open or available When the interest of any strike price is zero.

Enjoy Zero brokerage on ALL Intraday Trades
+91 -

Enjoy Zero brokerage on ALL Intraday Trades
+91 -