Weekly options — often called “weeklys” — are short-dated options contracts that expire every Friday rather than the standard third-Friday monthly cycle. First introduced by the CBOE in 2005 on the SPX index and expanded to equities around 2010, weeklys now represent approximately 30–40% of all U.S. equity options volume. Their defining characteristic is compressed time value: because they expire in 1–7 days, theta decay is front-loaded and accelerates sharply in the final 48 hours.
Key Takeaways
- A near-the-money weekly option with 5 DTE does not carry 5x the time value of a 1-day option — due to the square-root-of-time relationship, it holds roughly 2.2x, meaning decay is faster than most buyers expect.
- Gamma risk dominates as expiry approaches: a near-the-money SPY weekly can move from delta 0.30 to near 1.0 within a single volatile session two days before expiry.
- Bid-ask spreads on low-premium weeklys are proportionally punishing — a $0.50 option with a $0.05 spread carries a 10% round-trip cost before the trade has a chance to work.
How Weekly Options Work
Weekly options follow the same mechanics as standard options — they carry a strike price, an expiration date, and are priced using the same Black-Scholes inputs — but the compressed timeline changes the risk profile materially.
Settlement type matters for index options. SPY (ETF) weeklys settle PM on Friday — the closing price determines exercise. SPX weeklys that expire on Wednesday settle AM, meaning they settle to Friday morning’s opening print, not Thursday’s close. A trader who holds an SPX Wednesday weekly overnight on Thursday has no way to exit at a known settlement price — the position pins to an opening auction they cannot control.
Theta decay is not linear. Decay follows a square-root-of-time relationship. A $2.00 option with 5 DTE may lose $0.60 on day 4 alone — roughly 30% of its remaining value in a single session. A buyer needs the underlying to move significantly and quickly just to break even against time decay.
Gamma is the other side of that coin. For sellers, gamma risk near expiry is the primary concern. A 1-point move in SPY on Wednesday with Friday expiry can push a $520 strike from delta 0.30 to delta 0.80 within hours. Iron condors and spreads that were comfortably out-of-the-money on Monday can be deeply tested by Thursday.
Quick Reference
| Aspect | Detail |
|---|---|
| Expiry Cycle | Every Friday (some underlyings have Monday/Wednesday expirations too) |
| Time Decay Rate | Accelerates exponentially; final 48 hours account for 30–40% of remaining value |
| Key Risk (Buyers) | Theta destruction even when directional view is correct |
| Key Risk (Sellers) | Gamma explosion on gap moves near expiry |
| Settlement (SPY) | PM settlement — Friday closing price |
| Settlement (SPX Wed) | AM settlement — Friday opening print |
| Volume Share | ~30–40% of total U.S. equity options volume (CBOE) |
Practical Example
SPY is trading at $520 on Monday morning with no major catalysts expected through the week. A trader sells a weekly iron condor: sell the $515 put / buy the $512 put, sell the $525 call / buy the $528 call. The net credit collected is $0.90 ($90 per contract). Max loss is $2.10 ($210 per contract). The breakeven range is $514.10–$525.90.
By Wednesday, SPY sits at $521. The position has decayed to $0.30. The trader buys it back for a $60 profit ($0.60 gain × 100 shares per contract) in two days without SPY moving against the position at all — theta did the work.
Now contrast with a directional buyer. A second trader buys the $525 call for $0.45 on Monday, expecting a breakout. SPY closes at $522 on Friday. The call expires worthless. The buyer was directionally close — SPY moved up — but the move was too small to overcome five days of theta decay on an out-of-the-money strike. The buyer lost 100% of premium.
This asymmetry is why bid-ask spread discipline matters. A $0.45 call with a $0.05 spread means the buyer is starting 11% underwater before the first tick.
Weekly options expire every Friday and lose time value much faster than standard monthly contracts. In the final two days before expiry, a two-dollar option can lose sixty cents in a single session, making them risky for directional buyers but attractive for premium sellers using defined-risk strategies.
Common Mistakes
- Buying OTM weeklys without a binary catalyst. Theta decay is unforgiving on a 5-day contract. Without an earnings report, Fed announcement, or CPI print to drive a sharp move, directional buyers are fighting time decay every hour.
- Ignoring AM settlement on SPX weeklys. Holding a Wednesday-expiry SPX position overnight Thursday exposes traders to Friday’s opening gap — a price they cannot exit before it sets.
- Underestimating gamma near expiry. A position that looks safe at delta 0.15 on Tuesday morning can be at delta 0.70 by Thursday afternoon on a 1% move in the underlying. Sellers who don’t monitor actively get overrun.
- Treating wide bid-ask spreads as negligible. On a $0.50 premium, a $0.10 wide market is a 20% round-trip cost. Entering and exiting at market on weekly options with thin liquidity systematically destroys edge.
How JournalPlus Tracks Weekly Options
JournalPlus lets traders tag each options trade with days-to-expiry at entry, IV rank, and delta — the three inputs needed to separate repeatable edge from random variance in weekly strategies. Filtering P&L by DTE bucket (1 DTE vs. 5 DTE) and IV rank range reveals whether a strategy’s returns hold up across market conditions or are driven by a handful of outlier weeks.
