Term Structure and Covered Calls in a Low-Volatility Environment

When summer trading is slow, and everyone’s either at the beach or wishing they were, implied volatility (IV) can get pretty low. For covered call sellers, lower IV means bringing in less premium. That doesn’t mean you have to give up your covered call strategy altogether, nor does it mean you have to live with lower premiums. But it might require a shift in your thinking, and perhaps your strategy.

Change Your Strike Price? Or Change Your Expiration Date?

To offset low volatility, you could choose a strike closer to at-the-money, but that will increase the likelihood of having your stock called away if the option is in the money at expiration.

Alternatively, you could move your strike selection further out in time. Some covered call sellers prefer to stick to calls with less than a month until expiration, because short-term options tend to decay more quickly than long-term options. But the choice might depend on what the volatility curve is doing. Also called the “term structure,” the volatility curve is a graphical representation of the implied volatility levels at each expiration.

Why does the term structure matter? When implied volatility levels are all pretty much the same from expiration to expiration, or when the shorter-term expirations are higher than the longer-term, selling a shorter-term option over multiple expiration cycles can bring in more premium collectively than selling one longer-term option would.

Let’s say, for example, that XYZ is trading for $50. The 55-strike call ($5 OTM) expiring in a month is trading for $1, and a three-month 55-strike call is trading for $2.50. You could sell the call for $1 today, and if the option stays OTM at expiration, and IV stays about the same, you could sell another call that’s $5 OTM for $1 or so, and again the following month if conditions remain the same. Over the three-month period, this strategy would have brought in about $3, which is more than the $2.50 for the three-month option. But don’t forget those transaction costs, which can pile up with the monthly strategy.

Consider the Term Structure

There are times when shorter-term volatilities are so much lower than the further out volatilities that the longer term might be worth considering. And that can certainly be the case when IV is low. For example, figure 1 shows the term structure of futures contracts based on the CBOE Volatility Index (VIX), a measure of the 30-day IV of the S&P 500. The steep upward slope of the curve shows the market’s expectation of higher IV in the future. During periods of low volatility, many stocks reflect a similar term structure. 

Your stock may have a similar volatility curve. Here’s an example with some theoretical numbers. Let’s say a stock’s trading around $146 and the 150 call option with 24 days left to expiration is worth about $0.45. See the table below. This is the “summertime” implied volatility, and it’s 10%.

Comparison of 24- and 52-day options. The longer-dated option, with higher implied volatility, has a much higher theoretical value. Sample data. For illustrative purposes only.

You could sell this call and collect $0.45, and if the stock price and implied volatility are the same in 24 days, you could possibly sell another call for $0.45. That would give you $0.90 of premium collected over 48 days. Of course you would have transaction costs on both trades, which would eat into that $0.90 compared to one trade.

However, if you instead sell the 150 strike that has 52 days until expiration and has an implied volatility of 14%, then you’d collect $1.20 in just one trade. That gives you 33% more premium than the $0.90 you collected from two trades, for about the same period of time.

Yes, summer can mean lower IV, and thus lower premium for covered call sellers, so it might help to look at the term structure to help determine the most appropriate trade for your objectives.