What is Open Interest?

Open Interest is the total number of outstanding contracts that are held by market participants at the end of the day.

It can also be defined as the total number of futures contracts or option contracts that have not yet been exercised (squared off), expired, or fulfilled by delivery.

Open interest applies primarily to the futures market. Open interest, or the total number of open contracts on a security, is often used to confirm trends and trend reversals for futures and options contracts.

Open interest measures the flow of money into the futures market. For each seller of a futures contract there must be a buyer of that contract. Thus a seller and a buyer combine to create only one contract.

Therefore, to determine the total open interest for any given market we need only to know the totals from one side or the other, buyers or sellers, not the sum of both.

The open interest position that is reported each day represents the increase or decrease in the number of contracts for that day, and it is shown as a positive or negative number.

How to calculate Open Interest?

Each trade completed on the exchange has an impact upon the level of open interest for that day.

For example, if both parties to the trade are initiating a new position ( one new buyer and one new seller), open interest will increase by one contract.

If both traders are closing an existing or old position ( one old buyer and one old seller) open interest will decline by one contract.

The third and final possibility is one old trader passing off his position to a new trader ( one old buyer sells to one new buyer). In this case the open interest will not change.

Importance of Open Interest

Open interest is a crucial metric in the futures and options markets, reflecting the total number of outstanding contracts. It provides valuable insights into market sentiment, liquidity, and potential price trends.

Rising open interest indicates growing market participation and suggests potential price trends, while declining open interest may signal a market reversal. Traders and analysts use open interest to gauge market dynamics, identify trading opportunities, and manage risk effectively in derivative markets.

Using Open Interest for Trading

Traders often use open interest in conjunction with price movements to interpret market dynamics. When prices rise along with increasing open interest, it suggests a bullish trend, indicating new positions are being established. Conversely, falling prices accompanied by rising open interest can signal a bearish trend as more contracts are added. However, divergences between price and open interest can also provide valuable information. For instance, if prices rise while open interest decreases, it may indicate that the current trend is losing momentum.

Here’s a simple interpretation table for open interest and price movements:

Price Movement Open Interest  Interpretation
Rising Increasing Bullish sentiment, potential uptrend.
Falling Increasing Bearish sentiment, potential downtrend.
Rising Decreasing Bullish trend weakening, possible reversal.
Falling Decreasing Bearish trend weakening, potential reversal.

It’s important to use open interest along with other fundamental and technical analysis tools to make well-informed trading decisions. Additionally, traders should be aware of market-specific factors and utilise risk management techniques to tackle potential losses.

Working of Open Interest

Open interest estimates the flow of money into or out of a futures or options market. An increase in open interest means new or extra money coming into the market, while a decrease in open interest signifies money flowing out of the market. It is essential to options traders as it offers insights into the liquidity of an option.

Example of Open Interest

The following table illustrates trading activity in the options market involving traders A, B, C, D, and E. Open interest is determined based on whether the traders bought or sold options to open or close positions.

Date Trader Action Change in Open Interest
January 1 A Buys from B (Open) +1
January 2 C Buys from D (Open) +5
January 3 A Sells to D (Close) -1
January 4 E Buys from C (Open) +5
January 4 C Sells to D (Close) -5

This sequence demonstrates how open interest fluctuates based on traders’ activities, whether they are opening or closing options positions.

  • January 1: Trader A purchases one option from Trader B, initiating a new position and increasing open interest by one.
  • January 2: Trader C acquires five options from D to establish new positions, resulting in a total open interest of six.
  • January 3: Trader A sells one option to D, closing a position and reducing open interest by one.
  • January 4: Trader E buys five options from C, initiating new positions. Simultaneously, C sells the five options obtained from D to close positions.

Open Interest and Volume 

Open interest and volume are the two important concepts in the futures market. Traders look at both to predict trends.

Let’s discuss them one by one. Though both OI and volume are quite similar, which often confuses new traders, they are not the same.

OI represents the number of open contracts in the futures market, in possession of individual buyers and sellers.

Now for the futures market, for every contract sold, there should be a buyer. So, the number of total contracts transacted in the day remains balanced. Volume refers to the total number of contracts executed during the day. So, if one contract is sold and bought, the volume goes up by one (pls note: the volume adds up by 1 and not 2 because only one contract passed between the buyer and seller).

At the beginning of the day, the volume is set to zero. Hence, you get a clear picture of the number of contracts exchanged hands during the trading hours. Open interest is not as discreet as volume. The value of open interest may remain unchanged or change depending on the number of traders entering or exiting the trade.

Let’s discuss further with the help of an example. Consider there are three traders in the market, A, B, and C.

On day one, seller B sells 8 futures contracts, and Buyer A buys all eight. So, after day one, both volume and open interest stood at eight.

Next day, A sells five contracts and C buys five contracts. At the end of the second day, volume changes to five (number of contracts changed hands); but open interest remains unchanged at eight because no new contract was created in the market.

It is important to note that volume changes daily, but the open interest may remain unchanged for days. Open interest will remain the same unless new contracts are initiated, or the old ones are settled or executed.

Benefits of monitoring open interest

By monitoring the changes in the open interest figures at the end of each trading day, some conclusions about the day’s activity can be drawn.

Increasing open interest means that new money is flowing into the marketplace. The result will be that the present trend ( up, down or sideways) will continue.

Declining open interest means that the market is liquidating and implies that the prevailing price trend is coming to an end. A knowledge of open interest can prove useful toward the end of major market moves.

A leveling off of open interest following a sustained price advance is often an early warning of the end to an uptrending or bull market.

Is Higher Open Interest Better?

High open interest often signifies increased contract liquidity. This enhances the ease of trading, as there’s less discrepancy between what sellers demand and what buyers are willing to pay. Additionally, a rising open interest suggests the prevailing market trends associated with that option are likely to continue.

Is Open Interest Bearish or Bullish?

An increase in open interest typically indicates new buying activity, reflecting a bullish sentiment. However, extremely high open interest levels can sometimes serve as a bearish signal, hinting at a coming shift in market trends.

What Happens When Open Interest Increases?

A rise in open interest typically indicates fresh capital entering the options market, supporting the ongoing trend. Conversely, when open interest declines, it suggests market participants are exiting, potentially leading to the conclusion of the prevailing price trend.

Conclusion :

Hope you have now got a fair idea of: what is open interest? Now here is a word of caution. If you see that there is a lot of open position along with significant price change, refrain from entering the market. It is an indication that the market is in the grip of an unexplained over-enthusiasm. When it happens, even a small trigger is enough to cause panic among traders. If it happens then, everything will come crashing down.


Where can i find tickets?

Open interest is critical to determine liquidity in the options market. If there is no open interest for the contracts, it means, there is no secondary market. On the other hand, a sufficient number of open interests indicates an active market with a large number of buyers and sellers.

What does open interest indicate?

Open interest signifies quite a few things in the futures market.

  • It indicates the available number of unsettled futures contracts with individual buyers and sellers
  • Essentially, the number of open interest contracts also signifies liquidity
  • It helps predict the market trend
  • Together open interest and volume help traders make better trading decisions

What is the use of open interest?

Traders in the derivative market use the open interest to determine demand. It is a more accurate measurement of options trading activities and the flow of money, whether increasing or decreasing. And in doing so, open interest predicts market trend and reversal.

How do you trade with open interest?

There are quite a few ways to predict the market with OI and trade in the direction of the market.

  • If the OI number is rising along with an upward movement in price action, the market is considered bullish
  • When price movement remains upward but accompanied by a decline in OI, the market is then bearish
  • When both OI and price are dipping, it indicates mounting pressure among traders as the bear takes the charge
  • A drop in price action but increase in OI also indicates a bear trend

What is the highest open interest?

High OI means that there are contracts available for trading. As OI only goes up when new or additional money is coming in the market, increasing OI indicates the presence of new buyers and sellers. Decreasing OI indicates an outflow of money.