An options strategy structured so time decay works in the trader's favour, earning profit simply as expiry approaches.
A theta-positive strategy is any options position whose net theta is greater than zero, meaning the position gains value each day purely from the passage of time, all else being equal. This is the mirror image of buying options, where time decay is the enemy; theta-positive strategies are built by selling options, or structuring spreads so the sold options outweigh the bought ones, so decay becomes a source of profit rather than a cost.
Common theta-positive strategies among Indian retail F&O traders include selling covered calls (see covered call) against existing stock or futures holdings, credit spreads, short strangles, and short straddles on Nifty or Bank Nifty around weekly expiry. Because weekly index options decay fastest in their final days, many traders specifically initiate theta-positive positions early in the week and look to close or roll them before expiry-day gamma risk becomes too large.
The rate of decay is not linear, it follows the theta decay curve, which stays relatively flat when there are many days left to expiry and steepens sharply in the last few sessions, especially for at-the-money strikes. This is precisely why option sellers favour shorter-dated weekly contracts: the accelerated decay in the final days generates a larger share of the total premium erosion in a shorter holding period, letting sellers collect time value faster.
The trade-off is that theta-positive strategies are almost always gamma-negative, meaning they are vulnerable to sudden, sharp moves in the underlying. A single volatile session, a surprise RBI announcement or a global shock overnight, can erase weeks of steadily collected theta in one move, which is why theta-positive strategies are typically paired with defined-risk structures or strict stop-loss discipline rather than run as uncapped naked positions.
Got a question or a feature you wish existed? Drop it in our Telegram community, the Stolo team is right there reading every message.