Open Interest Additions and Unwinding

Two Fridays, One Number

Kavya had been at the brokerage in Pune for six weeks, and she'd finally started to feel comfortable with the derivatives sheet Vikram made her check every morning. Rows of numbers, one of them called Open Interest — she knew it was just a headcount of how many futures contracts were still open on a stock. Nothing scary about a headcount.

That Friday afternoon, she was closing her notebook when something made her flip back two pages. Three weeks ago, same stock, same contract, same Friday of the week — the Open Interest number was 42,500. And today's number, three weeks later, was also 42,500.

"Vikram," she said, turning her screen toward him. "This is odd. Exact same OI, both Fridays. But three weeks ago everyone on the floor was buzzing — people kept saying the stock had 'real strength.' Today it's quiet, almost nervous chatter. Same number. Totally different mood. Shouldn't the number tell the same story both times?"

Vikram rolled his chair over, glasses pushed up on his forehead. "What was OI the day before each of those Fridays?"

Kavya hadn't thought to check. She scrolled back. Three weeks ago, Thursday's OI was 39,800 — lower than Friday's 42,500. Today, Thursday's OI was 45,100 — higher than today's 42,500.

She stared at the two numbers sitting on either side of the same 42,500, like two roads arriving at the same signboard from opposite directions.

"So... one Friday the number climbed up to 42,500," she said slowly, "and this Friday it came down to 42,500."

"Right," Vikram said. "Now ask yourself — what has to happen for a headcount of contracts to climb? And what has to happen for it to fall? Those aren't the same event just running backwards. Something different is happening to real people's money each time."

Kavya looked at the two identical numbers again, no longer feeling like she understood them at all.

• Explain why rising Open Interest means new contracts are being created, with a new buyer and a new seller both entering for the first time.
• Explain why falling Open Interest means existing contracts are being unwound, with an existing buyer and seller both exiting together.
• Recognize that every OI change, up or down, requires two willing counterparties acting together, never one side alone.
• Distinguish the raw OI level (a snapshot) from the change in OI (a trend) as two separate, useful pieces of information.

Kavya's puzzle has a simple answer, and once you see it, you'll never look at Open Interest the same way again.

Open Interest only ever moves for one of two reasons. It rises when fresh contracts get created — and a fresh contract can't exist unless a new buyer and a new seller both show up and agree to it. Nobody creates a contract alone. So when you see OI climb, what actually happened is: two new people just entered the market on that contract, one betting up, one betting down, and both agreed to open a position.

Open Interest falls for the opposite reason. It's not "the new buyer and seller from before leaving one at a time." It's an existing buyer and an existing seller, who were already holding opposite sides of the same contract, both agreeing to close it out together. That's called unwinding — think of it as undoing a deal, not breaking it apart. One side can't unwind without the other agreeing to exit too, because a contract only ends when both parties let go of it at the same time.

The number alone can't tell you which of these happened — you have to look at where it came from.

This is why the same OI number can mean two completely different things on two different days. 42,500 reached by climbing up from 39,800 tells you: new money, new positions, fresh conviction entering. 42,500 reached by falling from 45,100 tells you: old positions being packed up and closed, people stepping away. Same headcount, opposite story.

The number alone can't tell you which of these happened — you have to look at where it came from.

That's the real lesson from Level 5 extended one step further. Level 5 taught you that OI is just a headcount, a snapshot — it doesn't tell you direction on its own. Now you know that the change in that headcount is a completely separate piece of information, sitting on top of the level, telling you whether fresh conviction is building or existing positions are being unwound. A level tells you how many. A change tells you what's been happening. You need both.

Back at her desk, Kavya pulls up the full week's sheet instead of just the Friday snapshot she'd been staring at.

For the first Friday — the one everyone remembers as buzzing with "real strength" — she checks Thursday's close: OI was 39,800. By Friday it had climbed to 42,500. That's a jump of 2,700 contracts in a single day. Kavya writes it out for herself: for each of those 2,700 new contracts, one new buyer and one new seller had to show up and agree to trade. Fresh money, fresh conviction, both sides stepping in for the first time. That explains the buzz — a lot of new participants had just placed a bet on this stock, in either direction.

For the second Friday — quiet, nervous chatter — she checks that week's Thursday: OI was 45,100. By Friday it had dropped to 42,500, a fall of 2,600. Kavya realizes these weren't new people arriving. These were 2,600 existing contracts being closed — an existing buyer and an existing seller on each one both deciding to exit together. People weren't stepping in; they were stepping out.

"So the number 42,500 shows up twice," Kavya says, "but the first time it's the result of 2,700 people just walking in, and the second time it's the result of 2,600 people just walking out."

Vikram nods. "That's why we never trust the level by itself. We always ask: compared to yesterday, did this go up or down — and by how much?"

Kavya circles both Thursday numbers in her notebook, right next to the two identical Fridays. Same destination, two very different roads to get there.

Point: The same OI level can be reached by rising or falling paths, and only checking the change (versus the prior reading) reveals which happened — reinforcing that level and change are two distinct pieces of information.

• Treating a rising or falling OI number as a signal that predicts what the price will do next. — Once a number is shown to 'mean something' about buyers and sellers, it feels natural to jump from 'this changed' to 'so this is where it's headed.' Fix: Remind yourself that OI change describes what has already happened — contracts already opened or already closed. It's a clue about current conviction, not a forecast. Treat it as history, not prophecy.
• Assuming rising OI means 'more buyers than sellers' pushed it up, or falling OI means 'more sellers than buyers' pushed it down. — Everyday market talk about 'buying pressure' and 'selling pressure' makes it easy to picture one side acting alone. Fix: Remember every addition needs a new buyer AND a new seller to agree, and every unwind needs an existing buyer AND an existing seller to both agree to exit. OI never moves because of one side alone.
• Believing that once you know OI is 'just a headcount,' there's nothing more to learn from it. — The earlier lesson on OI as a snapshot feels complete, so the change in OI seems like an unnecessary extra layer. Fix: Treat the level and the change as two separate questions: 'how many contracts are open right now' and 'is that number growing or shrinking, and by how much' — both are worth checking, every time.

• Rising Open Interest means new contracts are being created — a new buyer and a new seller are both entering for the first time.
• Falling Open Interest means existing contracts are being unwound — an existing buyer and existing seller are both exiting together.
• No OI change ever happens one-sided — every addition and every unwind needs two willing counterparties to agree.
• The OI level tells you the count; the change in OI tells you the trend behind that count — check both before forming a view.
• OI change describes what has already happened — it's a clue about conviction, not a guarantee of what comes next.

Q1. What does a rising Open Interest number mean?

• New contracts are being created, with a new buyer and a new seller both entering
• Existing contracts are being closed out by an existing buyer and seller
• Only new buyers are entering the market
• The price of the stock is guaranteed to go up Answer: New contracts are being created, with a new buyer and a new seller both entering — Rising Open Interest means fresh contracts have been created — and a fresh contract can only exist if a new buyer and a new seller both agree to open it.

Q2. True or False: Open Interest can fall because only the sellers in existing contracts decide to exit, while the buyers stay in. Answer: False — A contract can only close when both sides agree to exit together. Falling OI always means an existing buyer and an existing seller both unwind their positions at the same time — never just one side.

Q3. Why is it useful to know both the OI level and the recent change in OI, rather than just the level?

• Because the level tells you the count, while the change tells you whether that count was reached by fresh contracts forming or old ones closing
• Because the change in OI tells you exactly what the price will do next
• Because the level is unreliable and only the change matters
• Because the two numbers are always identical and checking both confirms accuracy Answer: Because the level tells you the count, while the change tells you whether that count was reached by fresh contracts forming or old ones closing — The same OI number can be reached by rising from a lower value (new contracts forming) or falling from a higher value (contracts being unwound) — the level alone can't reveal which happened, but the change can.

Q4. On Monday, a stock's futures contract has an Open Interest of 10,000. On Tuesday, it rises to 12,500. What most likely happened between Monday and Tuesday?

• About 2,500 new contracts were created, each with a new buyer and a new seller agreeing to open a position
• About 2,500 existing buyers exited while their matching sellers stayed in
• The price of the stock definitely went up
• 2,500 existing contracts were unwound by buyers and sellers exiting together Answer: About 2,500 new contracts were created, each with a new buyer and a new seller agreeing to open a position — Since OI rose from 10,000 to 12,500, fresh contracts were added — each one requiring a new buyer and a new seller to both step in for the first time.

Q5. OI on a contract drops sharply in one session. A trader posts: "OI crashed, the price is definitely about to crash too." Does falling OI guarantee the price will fall? Reveal: Weak: yes, falling OI always drags price down with it. Strong: falling OI only tells you existing contracts were unwound, a description of the past, not a guaranteed future price move — positions closing can happen during a rising or falling price.