Constructing credit spreads around settlement and implied volatility

Treat construction as one checklist

A credit spread is built by selling a near-the-money or at-the-money option and buying an out-of-the-money option of the same type. The pair can be puts or calls. The nearer strike is sold and the farther strike is bought, and the structure is opened for a net credit so the long option caps the short-leg payoff.

Editorial reading: TradersWeek treats that structure as one checklist rather than three separate decisions. Lock the exercise calendar first, then place the short and long legs so implied-volatility richness stays on the sold strike instead of being cancelled by two in-the-money deltas.

Lock the exercise calendar first

S&P 500 index options settle European-style and can be exercised only at expiration. Most index options settle European-style. S&P 100 index options settle American-style and can be exercised or assigned before expiration.

Exchange-traded-fund options and stock options settle American-style and can be exercised at any time before expiration. Credit-spread construction that needs to avoid early assignment is described as better suited to a European-style index than to an American-style fund or stock option.

Settlement style, remaining days, and assignment timing belong in the construction, not after the strikes are already chosen.

Place the short strike, then the long strike

The short leg is the near-the-money or at-the-money option. The long leg is a farther out-of-the-money option of the same type. That pairing is the defined-risk structure: one option is sold and another of the same type is bought so the short-leg payoff is capped.

In the construction example, selling a 50-strike call for 4 and buying a 55-strike call for 1 opens a 3-point credit. Both calls expire worthless if the underlying is at or below 50 at that expiration.

If the underlying is at 55 at expiration, the short 50-strike call is subject to assignment while the long 55-strike call expires worthless. The long call only offsets further upside beyond 55.

Keep implied volatility on the sold strike

Implied volatility is the volatility priced into option premiums. It is used here to judge whether the sold strike is rich relative to the protective long.

A high-implied-volatility, low-delta construction keeps the short leg expensive relative to a farther out-of-the-money long. Pairing high delta with high implied volatility tends to put both legs in the money and shrinks the implied-volatility gap between them.

Delta is the estimated change in an option's value for a one-point move in the underlying, and it is higher for in-the-money strikes than for out-of-the-money strikes. Editorial reading: once both legs are in the money, the implied-volatility contrast the short strike was meant to keep is already being cancelled.

A stated strike and calendar template

One stated construction places the short strike at-the-money or slightly out of the money, the long strike farther out of the money, and about 30 days until expiration. The at-the-money strike is at or nearest the current underlying price and is typically used for the short leg. The out-of-the-money strike sits beyond the current underlying price and is typically used for the protective long leg.