Saturday, May 18, 2013 EST

The goal of option sellers is to sell contracts with the goal of the contract losing value (primary goal of expiring worthless) so that the seller keeps the cash.  There have been many articles on the weekend effect for both stocks and options. Option sellers can take advantage of the drop in premium by selling options later in the week.

The article "The Weekend Effect in Equity Options" published on SSRN discusses this concept and that on average options lose 0.6% of value over the weekend.

Options losing value over the weekend can be magnified even more by selling options that expire the next week out, since time is running out and time value starts slipping away even faster! Weekly options can be a good choice for this type of trading strategy. Using our Expert Option Screener an option trader can easily screen for options that expire one or weeks out to find these types of trades.

Article Summary (from the authors): "We find that returns on options on individual equities display markedly lower returns over weekends (Friday close to Monday close) relative to any other day of the week. These patterns are observed both in unhedged and delta-hedged positions, indicating that the effect is not the result of a weekend effect in the underlying securities. We find even stronger weekend effects in implied volatilities, but only after an adjustment to quote implied volatilities in terms of trading days rather than calendar days." 

"Our results hold for puts and calls over a wide range of maturities and strike prices, for both equally weighted portfolios and for portfolios weighted by the market value of open interest, and also for samples that include only the most liquid options in the market. We find no evidence of a weekly seasonal in bid-ask spreads, trading volume, or open interest that could drive the effect. We also find little evidence that weekend returns are driven by higher levels of risk over the weekend. 

"The effect is particularly strong over expiration weekends, and it is also present to a lesser degree over mid-week holidays. Finally, the effect is stronger when the TED spread and market volatility are high, which we interpret as providing support for a limits to arbitrage explanation for the persistence of the effect." - Christopher S. Jones & Joshua Shemesh

Additional Reading

Weekend Effect and Stock Returns - Kenneth R. French