In this snippet from an option chart from CBOE website

enter image description here

I am guessing that the chart is showing Call Options for Apr 25, 2014 expiry for the Strike of 155. But how come there are so many calls for same expiry and same strike? If we see the SPY option chain on yahoo finance each strike and expiry has just one record.

  • Your assertion that "each strike and expiry has just one record" does not seem accurate. If you look closely you'll see many repeated price points on that Yahoo page.
    – dg99
    Apr 23, 2014 at 17:56
  • Thanks. But should there not be just one price for each strike and expiry?
    – Victor123
    Apr 23, 2014 at 18:07
  • Yes, your question is still valid, I just wanted to point out that Yahoo Finance shows similar listings to the CBOE. Btw, I believe the answer is related to the subtle different in instrument names. If you read the symbols very carefully on the Yahoo site you'll notice that they differ by one letter or number just after the SPY prefix. I just don't know what that one character signifies.
    – dg99
    Apr 23, 2014 at 20:34

1 Answer 1


The CBOE site, as well as some other sites and trading platforms, will show the bid/ask and statistics for that option at each individual options exchange, in addition to statistics and the best bid/offer across all exchanges.

cboe.com: Delayed Quote Help lists what the single-letter codes mean. A is for the AMEX options exchange, B is for BOX, X is for PHLX, etc.

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