Understanding the difference between the option chain and option flow—and how open interest works—helps you interpret TradingFlow data and confirm whether big trades were opening or closing.

Option Chain vs Option Flow

• Flow shows what’s happening in the moment.
• Chain shows cumulative positioning (OI) and levels (e.g. call/put walls).
• Tomorrow’s OI is partly today’s flow: new positions that are held overnight show up as higher OI the next morning.

Open Interest (OI)

Open Interest is the total number of option contracts that are still open (not closed or expired).

• Volume = contracts traded today (resets daily).
• OI = total open contracts across all days (cumulative).

So volume is "how much traded today"; OI is "how much is still on the books."

OI Update Frequency

OI is not real-time. The Options Clearing Corporation (OCC) updates it overnight, typically before the next open (e.g. ~6:30 AM ET). During the day, the OI you see is yesterday’s closing OI. Today’s trades (volume) won’t change OI until the next morning.

OI Change and Trade Intent

We use change in OI from one day to the next to infer whether flow was opening or closing:

• Opening: High volume and OI goes up next day → strong signal that new money is taking a position.
• Closing: High volume and OI goes down → positions are being exited.
• Churn: High volume, OI flat → positions changing hands or day trades; less directional signal.

T+1 Confirmation

To confirm that a large trade was opening, check the next morning’s OI:

• ΔOI ≈ trade size → Confirmed opening (position held overnight).
• ΔOI ≈ 0 → Likely day trade or churn.
• ΔOI < 0 → Confirmed closing.

In unusual options activity, we often assume aggressive (ask-side) sweeps are opening until T+1 OI proves otherwise, since institutions usually don’t sweep to exit.

For where this data lives in the product, see Data Schema.

理解期权链与期权流的区别，以及未平仓合约的运作方式，有助于您解读 TradingFlow 数据，并确认大额交易是开仓还是平仓。

期权链 vs 期权流

• 流量显示当下发生的事情。
• 期权链显示累计仓位（OI）和价位（如看涨/看跌墙）。
• 明天的 OI 部分来自今天的流量：隔夜持有的新仓位将在第二天早晨显示为更高的 OI。

未平仓合约（OI）

未平仓合约是仍处于开放状态（未平仓或未到期）的期权合约总数。

• 成交量 = 今天交易的合约数（每天重置）。
• OI = 所有日期的开放合约总数（累计）。

因此成交量是"今天交易了多少"；OI 是"账簿上还有多少"。

OI 更新频率

OI 不是实时的。期权清算公司（OCC）在隔夜更新，通常在下一个开盘前（如美东时间约 6:30 AM）。在交易日中，您看到的 OI 是昨天的收盘 OI。今天的交易（成交量）直到第二天早晨才会改变 OI。

OI 变化与交易意图

我们使用相邻两天的 OI 变化来推断流量是开仓还是平仓：

• 开仓：高成交量且第二天 OI 上升 → 强烈信号，新资金建立仓位。
• 平仓：高成交量且 OI 下降 → 仓位被平仓。
• 频繁换手：高成交量但 OI 持平 → 仓位换手或日内交易；方向性信号较弱。

T+1 确认

要确认大额交易是开仓，请检查第二天早晨的 OI：

• ΔOI ≈ 交易规模 → 确认开仓（仓位隔夜持有）。
• ΔOI ≈ 0 → 可能是日内交易或频繁换手。
• ΔOI < 0 → 确认平仓。

在异常期权活动中，我们通常假设激进的（卖价侧）扫单是开仓，直到 T+1 的 OI 证明否则，因为机构通常不会通过扫单方式平仓。

有关该数据在产品中的位置，请参阅数据 Schema。