Strike prices and GPS

Richard Ho
March 26, 2018
4 minutes read
Strike prices and GPS

One day I was driving home after work and I received a call from an old friend, Alex. We started talking about the kids and the wife but, eventually, we ended up talking about the markets. Alex has some knowledge of options, but there was one thing that he didn’t understand. He asked me, “How do you know which strike price to use?” It was a legitimate question. As a matter of fact, many investors I meet ask me the same thing: How do you select a strike price? So, I answered him with another question: “Alex, how do you use your GPS?” He told me to stop joking around, but I was serious, because selecting an option strike price is the same thing as using a GPS: you need to know where you are going, your destination. If not, there is no point to having a GPS, just like options. Now I will share with you what I told Alex that day about option strike prices and GPSs.

For simplicity’s sake, I will stick with a call option. For those of you who may be unfamiliar with options, a call option gives the owner the right (but not the obligation) to buy the underlying stock at a given price (called a strike price). This call option gives the holder the right to buy the stock at any time until the option expires.

When you turn on a GPS, you have to tell it where you want to go and then it will give you the optimal route. The same thing is true of options (this applies to calls and puts): you need to have an expected target price. An expected target price is what you think the share price could be in the future. If you are new to target prices, you can find them in analyst reports or by using the technical analysis tools provided by your online broker.

Let’s go back in time so I can show you an actual example using Teck Resources Limited (TECK.B). In the candlestick chart below, on a few occasions (between December 2016 and April 2017) the share price climbed up into the low-mid 30s and then pulled back.

On June 21, 2017, the stock closed at $20.37. If we assume that it will rally back to $30, we can express this view by purchasing a call option (expiring on August 18, 2017).

The expected target price of $30 is equivalent to the final destination that we enter into a GPS. Whether or not we get there is another story. As long as we have an expected target price, we can reverse-engineer the route in order to find the optimal strike price that will give us the greatest return.

Expected target price: $30

Return formula: 

(Expected target price – Strike price – Price paid for the call option)

            Price paid for the call option


Simply apply the return formula to all the strike prices on the call options expiring on August 18, 2017. The strike price that yields the greatest expected return (in this case, $27) will be the one to use for this trade.

On expiry of the options (on August 18, 2017), Teck Resources Limited had rallied to $29.34. Anyone who had bought the $27 call options for $0.14 could have made a 1,571% return. And if the stock didn’t go our way, the maximum loss would have been $0.14 (or $14 per option contract).


Until next time, and may the best trades be with you.


By: Richard Ho, CAIA, DMS, FCSI, senior manager equity derivatives


Richard Ho
Richard Ho

Senior Manager, Equity Derivatives

TMX | Montréal Exchange

Richard Ho, senior manager equity derivatives at TMX Montréal Exchange has been in the financial industry for over 15 years. Prior to joining TMX in 2006, he worked with a national brokerage firm in executing trades for active and high net worth clients. In his current role as senior manager equity derivatives, Richard leads various education initiatives and partnerships with brokerage firms. His aim is to help self-directed investors adapt to the use of equity options with a focus on developing and strategizing option portfolios for directional trading with predefined risk parameters. He also runs programs to show investors how to use option strategies to generate consistent income and to hedge their portfolios during times of high volatility. Richard is a derivative market specialist (DMS) by designation and a Chartered Alternative Investment Analyst (CAIA®) charterholder. Striving to help investors elevate their knowledge about options, Richard is a proud member of the Fellow of the Canadian Securities Institute (FCSI®) and shows leadership through various speaking and academic contributions.

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