# Unusual OI growth shift toward puts

Canonical: https://halfonadouble.com/screens/unusual-put-oi-growth-shift
Data through: 2026-09-22 close
Publisher: Half on a Double

Where did the balance of call-versus-put OI growth shift unusually far toward puts on Sep 22, 2026?

Rising put OI with a growth advantage over calls, and a call-minus-put growth gap at least two standard deviations toward puts relative to its own prior year. The gap has its own standardized history; subtracting the separate call and put z-scores is not this measure. Requires 200 prior comparisons, 100,000 current contracts and 1,000 contracts on each side at the prior close. This measures the OI balance, not implied-volatility skew.

4 published matches, in the same order as the HTML screen.

| Ticker | Close (USD/share) | Open interest (contracts) | Call / put growth and gap surprise |
| --- | --- | --- | --- |
| [META](https://halfonadouble.com/stock/META) | 736.59 | 3,213,040 | Calls +6.7% · puts +16.7% · gap -10.0 pp · gap -3.88σ |
| [NVO](https://halfonadouble.com/stock/NVO) | 39.40 | 1,356,350 | Calls +5.0% · puts +11.9% · gap -6.9 pp · gap -3.84σ |
| [BTBT](https://halfonadouble.com/stock/BTBT) | 1.86 | 398,129 | Calls +4.4% · puts +13.2% · gap -8.8 pp · gap -2.82σ |
| [DHT](https://halfonadouble.com/stock/DHT) | 21.39 | 159,950 | Calls +0.0% · puts +22.2% · gap -22.2 pp · gap -2.81σ |

An em dash means unavailable or not applicable, not zero. [Definitions and limitations](https://halfonadouble.com/methodology.md).