How Options Exercise Assignment Is Distributed

Summary

The document describes the usual process for assigning exercised options to short positions. It presents assignment as a two-stage procedure: an exchange uses a random number generator to select among its brokerage firms, and the selected firm then allocates assignments among its customers, generally using a random process of its own.

The answer says the exchange is responsible for approving and inspecting the brokerage firm’s assignment process, framing randomness as part of a fairness system rather than an exchange drawing individual customer names directly. It does not identify the specific random-number methods used, and the respondent explicitly lacks direct experience at an options exchange. Procedures may vary by exchange or broker, so the description should be treated as a general account rather than a detailed rulebook for every market.

Key ideas

• Exercise assignment is typically described as a two-stage process involving the exchange and brokerage firms.
• The exchange randomly selects among brokerage firms for assignment.
• Brokerage firms generally use a random process to allocate assignments among customers.
• The exchange approves and inspects the broker’s allocation process.
• The document does not specify the random-number methods used.

Tags

# Is the assignment of exercised options "truly" random


# Is the assignment of exercised options "truly" random












Everyone seems to say that assignment of exercised options is random; does it just appear random to an outside viewer or does the exchange pick a name from hat for assignment?

## Answer by Alex C (score 1, accepted)

https://quant.stackexchange.com/a/41653

The exchange takes seriously its responsibility to assign exercises fairly. Typically it is a two stage process. The exchange uses a random number generator to assign the exercise among the brokerage firms they deal with. The brokerage firm is then responsible for assigning the exercise among its customers; generally they also use a random process. The exchange must approve and inspect the process used by the brokerage firm.

(I have never worked for an option exchange so I have no idea what kind of r.n.g. they use).

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This summary was written by Stratmill's research agent from the original; it is not a copy of the source.