As I understand I can just purchase options that trade 100 stocks. Are there possibilities to buy, lets say, a put option to sell just 5 stocks at a given strike price?

5 Answers 5


Traditional exchange traded options are for 100 shares.

There are post reverse split contracts that cover less than 100 shares but because of the adjustments, the terms of the contract have changed. These are often complex and should be avoided if possible.

The CBOE introduced 1/2 a dozen or so mini options about 6-7 years ago but the public never took to it.


In a few cases (but not many) yes. The SPX mini for example.

  • The underlying of Mini-SPX Index Options is Index (i.e. Points and Multiplier) so it does not relate to Stock Options (i.e. Number of Shares).
    – base64
    May 14, 2020 at 5:12

You can buy any option contract you want if you can find someone willing to take the other side of it; this is entirely common in real estate, for example.

In the case of publicly traded stocks, however, option contracts are standardized specifically so that they can be reduced to a simple code (I happen to be involved in some SFL 200515P00010000) and routed through automated trading and clearing systems. Based on experience, the institutions developing the standards decided that the standardized contract would be for 100 shares of the underlying, at certain prices (you usually can't trade an option at strike $11.21), expiring on certain days (Fridays, especially third Fridays). If you want to use public exchanges, it's take it or leave it. This dramatically reduces the transaction costs and thus improves liquidity.

(There are a few exceptions, such as when the contracts have to be "adjusted" for splits or similar, and "mini" options as @Philip mentioned, but in general, what's available is standard or nothing.)

  • Thx for the clarification. But why does it reduce transaction costs? If the standard was 10 shares, coudn't I set one order to buy 10 options each trading 10 shares? Wouldn't a 10 share standard render more liquidity? May 7, 2020 at 19:31
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    @rantanplanthesecond Standardization is what reduces transaction costs; there's nothing to negotiate, and automated systems can handle the transactions (or even trade on their own). The exchanges could have selected 10-share contracts, but traditionally, "round lots" of shares have been in quantity 100, and the options contract was selected to match. May 7, 2020 at 21:00
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    @rantanplanthesecond (As for why "round lots" of 100, it is mostly a matter of matchmaking efficiency. Before computerization, if you wanted to sell 37 shares and I wanted to buy 19, it would be a lot of work to match up orders to make everything balance. Encouraging trading in units of 100 reduced the chances of difficulty in matching counterparties.) May 7, 2020 at 21:02

The Options Clearing Corporation and the rest of the industry went through an initiative a few years ago to standardize options symbols (the Options Symbology Initiative or OSI) so that they could support mini options. These would be typically for 10 shares rather than 100, and many exchanges offered reduce fees for mini options over regular options... except Amex. It ran for a while but the volume didn't pick up, so it was abandoned.

Today, any option for less than 100 shares is usually called an 'adjusted series' which often results from some kind of corporate action in the underlying stock. Market makers are not obliged to quote them, so liquidity is poor.


No but you can buy a spread (buy a put and sell a cheaper put) if you are looking for a cheaper trade than just buying the put. However, your profit is more limited and it takes time to realize the maximum profit

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