Multi-leg options trade (spread legs)
A multi-leg options trade is a single strategy, such as a vertical spread, straddle or iron condor, executed as several option contracts at once. On a flow tape its legs appear as separate prints, and reading each leg alone as a directional bet is one of the most common flow-analysis mistakes.
Senzoukria · Glossary · Updated September 2026
At a glance
- Examples
- Verticals, calendars, straddles, strangles, butterflies, condors
- On the tape
- Separate prints per leg, often at the same instant
- Main risk
- Reading one leg as the whole trade
Why legs mislead
A trader who buys the 500 call and sells the 510 call as a spread expresses a limited bullish view with a capped payoff. On the tape the purchase can look like a large call buy and the sale like a large call sell, each suggesting a different story. A straddle buyer purchases both a call and a put and is betting on movement, not direction. Package trades are often priced as a whole, so individual legs may print inside or outside their own quotes, which also distorts side labels.
Worked example
Two prints arrive within a few milliseconds on the same underlying: 1,000 contracts of the 30-day 100 call at 2.29 and 1,000 contracts of the 105 call at 0.64. Read separately, they are 229,000 dollars of call buying and 64,000 dollars of call selling. Read as one bull call spread, the trader paid 1.65 per spread, 165,000 dollars in total, for a maximum gain of 5.00 per spread if the underlying finishes above 105.
Detecting legs
- Simultaneity: legs of a package are usually executed within milliseconds of each other.
- Matching sizes or simple ratios: 1:1 for most spreads, 1:2:1 for butterflies.
- Same underlying and related strikes or expiries.
- Exchange trade conditions can mark complex-order executions, when the feed provides them.
- None of these proves a package: two unrelated traders can print the same size at the same moment.
In Senzoukria
Option Flow tags prints MULTI when different contracts on the same underlying print with the same size within 25 milliseconds of one another. The rule is a stated heuristic: ratio spreads with unequal sizes are not caught, and coincidental prints can be grouped. When a print qualifies as a sweep it is tagged SWEEP or GOLDEN instead. The documentation notes that legs of a spread priced separately can defeat both rules.
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Frequently asked questions
- How can I tell a spread from two separate trades?
- Look for prints at the same instant, on the same underlying, with the same size or a clean ratio, on related strikes or expiries. Trade condition codes may identify complex orders when the data includes them. Without such codes, the grouping remains an inference.
- Do multi-leg trades matter for gamma exposure?
- Yes. A spread's legs partly offset each other's gamma and delta, so counting only one leg overstates the exposure created. Open interest captures both legs after the fact, but flow-based readings need the grouping to avoid double counting direction.