Why it matters
Open interest is the count of contracts that are open, as of the prior close. Volume is the count that traded today. On a quiet strike the two barely interact: a few contracts trade, most of the open interest sits untouched. When volume climbs past open interest, something else is happening. The trading cannot all be existing holders passing contracts to each other, because there were not enough contracts to pass. Somebody is opening.
That is why this ratio is one of the first filters in every flow scanner. A large trade on a strike with heavy existing open interest is ambiguous. The same trade on a strike where it dwarfs the open interest is far more likely to be a fresh position, and fresh positions are what flow traders are trying to see. In the Robinflow feed, the Volume and OI columns sit side by side, the Signals column flags a contract as Exceeds OI when today's volume has passed its open interest, and the Options Explorer can filter on volume over open interest directly.
The confirmation comes the next morning. When the exchanges publish updated open interest, a contract that saw real opening activity shows a jump. Robinflow surfaces that as the Open Interest next day column, which compares the next morning's figure with the print's size.
What it does not tell you
- It is not proof of opening. The same contract can be opened and closed within a day by different traders. Volume above open interest makes new positions likely, not certain. Only the next morning's open interest settles it.
- Open interest is a day old. It updates once, overnight. Everything you see during the session is measured against yesterday's count.
- A high ratio says nothing about direction. New positions can be bought or sold. Read the side token for that.
- Low open interest inflates the ratio. A strike with 20 contracts open goes to a ratio of 10 on 200 contracts of volume. Check the absolute size and premium too.
What it looks like in the data
At 12:43 pm on September 10, 2026, a single block of 35,000 NVDA call contracts printed at the ask on a strike that had under 10,000 contracts open.
NVDA $245 call, Dec 18, 2026 expiry. Exec BLOCK, side A, 35,000 contracts at $8.56 for $29.96M with the stock at $218.21. Open interest rose by 34,478 contracts, or 347%, by the next session. Not a recommendation.
| Field | Value | How to read it |
|---|---|---|
| Volume / OI at the print | 35,335 / 9,924 | Volume 3.6 times the open interest |
| Signals | Exceeds OI | Today's volume passed the contract's open interest |
| Next-day open interest | 44,402 (+34,478) | The position survived to the next session |
| Side · Exec · Premium | A · BLOCK · $29.96M | One buyer, at the ask, in one print |
Read together: the volume told you during the session that this was probably new. The next morning's open interest told you it definitely was. Whether the buyer was right about NVDA is a separate question the ratio cannot answer.
