Opened a 1-contract calendar put spread on SPY — STO 760P Oct 16, 2026 @ $12.775 (66 DTE) / BTO 760P Oct 30, 2026 @ $14.77 (80 DTE). Net debit $1.995/share ($199.50/contract). Peak modeled P/L ~$685.63 if SPY ≈ $760 on Oct 16 (14.9% below entry). Modeled profit ~$260.50 if SPY pins $771.91 on Oct 16. Max loss $199.50 (= net debit, defined risk). Modeled breakevens ~$758 and ~$787 on Oct 16. SPY spot $771.91 — short strike 1.55% OTM. Positive gamma, negative theta. Calendar span 14 days. BSM cross-check within 2.2% of basis. European-style, cash-settled (no early assignment).
Why This Structure
A calendar put spread at-the-money (760 strike, 1.55% below spot) — the structure exploits the differential theta decay between the two legs. The short Oct 16 leg decays faster than the long Oct 30 leg because it's closer to expiry (66 DTE vs 80 DTE). By the time Oct 16 expires, the short leg has lost substantial time value while the long leg still retains ~2 weeks of premium, producing a profit if SPY stays near $760.
Why a calendar spread over a long 760P outright? The long 760P Oct 30 outright costs $14.77/share ($1,477/contract) with unlimited downside payoff but full debit risk — it loses ~$1,000+ if SPY rallies. The calendar costs $1.995/share ($199.50/contract) — 7.4× cheaper — and profits from time decay and pin behavior rather than a directional drop. The trade-off: the calendar needs SPY near $760 on Oct 16 to capture max profit; if SPY gaps ±$20, the calendar loses.
Why a calendar spread over a vertical put spread? A vertical put spread (e.g., long 770P / short 760P) would express a directional bearish view with capped risk/reward — but the playbook's thesis is that SPY is more likely to consolidate in the $760-$780 range through Oct 16 (post-FOMC drift, no major catalyst). The calendar harvests time decay rather than direction. A vertical would need SPY to drop; the calendar needs SPY to stay still.
Why $760 strike specifically? 760 is the strike nearest the current spot ($771.91) on the put side that balances (1) ATM-like behavior at the short expiry — calendars work best when the short leg is near ATM at its expiry, maximizing the time-value harvest; (2) premium differential — the 760P Oct 16 at $12.775 vs Oct 30 at $14.77 gives a $1.995 debit, which is the cheapest of the nearby strikes; (3) P(pin) — BSM-implied ~30% probability SPY finishes between $758 and $787 on Oct 16 (the modeled profit zone). Tighter strikes (755, 765) would have similar profiles but different pin dynamics.
Why Oct 16 / Oct 30 expiries? The 14-day calendar span captures the differential theta decay. Oct 16 is the standard monthly (3rd Friday), with deep OI and tight spreads. Oct 30 is the following standard Friday (2 weeks later). The short leg at 66 DTE and long leg at 80 DTE gives a 14-day differential — enough to capture meaningful time-value decay on the short leg without excessive IV risk on the long leg. A wider span (e.g., Oct 16 / Nov 20) would cost more debit and have more IV exposure on the long leg.
Why SPY at this level? SPY closed Aug 11 at $771.91, near all-time highs, with VIX 15.45 (low-vol regime). The playbook's thesis is consolidation — SPY has rallied ~15% YTD and is due for a pause. The calendar is a low-cost way to express "SPY stays in the $760-$780 range for the next 2 months" with defined risk. If SPY breaks out to $800+ or drops to $740, the calendar loses — but the max loss is capped at $199.50.
Thesis
Why SPY, why now: SPY is at $771.91, within 1% of all-time highs, with VIX at 15.45 (low-vol regime). The macro setup favors consolidation: Fed is in a data-dependent hold (no cut expected at Sep 16-17 FOMC per market pricing), Q3 earnings are largely behind (most S&P 500 companies reported), and there's no major catalyst until the Oct 28-29 FOMC. The calendar put spread is a low-cost ($199.50) way to harvest time decay on a "SPY pins $760-$780" thesis with defined risk.
Why a calendar over alternatives: A long 760P outright costs $1,477 with unlimited downside payoff — but the thesis isn't "SPY crashes," it's "SPY stays flat." A 770/760 bull put spread would collect ~$2-3/share premium but require SPY to stay above $770 — too tight. A straddle (long 770C + long 770P) costs ~$25-30/share with unlimited both-side payoff but needs a big move. The calendar is the cheapest structure for the "SPY goes nowhere" thesis.
Why not just sell the 760P Oct 16 naked: The naked short put collects $12.775/share ($1,277.50/contract) but has $76,000 of downside risk (if SPY drops to $0) and requires $76,000 of buying-power reserve (or $76,000 capital if cash-secured). The calendar's long leg caps the risk at $199.50 and gives 14 days of additional time value to harvest. The naked short is a high-risk, high-capital trade; the calendar is a low-risk, low-capital trade.
Why 14-day calendar span: The 14-day differential (Oct 16 short / Oct 30 long) is the sweet spot for calendar spreads — enough time-value differential to harvest (~$1.995 debit reflects the 14-day premium), but not so wide that the long leg has excessive IV exposure. A 7-day span (e.g., Oct 16 / Oct 23) would have less debit but also less harvest potential. A 30-day span (e.g., Oct 16 / Nov 13) would have more debit and more IV risk on the long leg.
Risk
| Risk | Magnitude | Mitigation |
|---|---|---|
| SPY gaps ±$20+ on macro news (geopolitical, Fed surprise) | Calendar loses $100-199.50 (debit) if SPY moves outside $758-$787 zone on Oct 16 | Hard stop at 1.5× debit ($299 cost to close) OR SPY closes below $740 or above $800 before Oct 1. The calendar is a pin trade — big moves are the enemy. |
| SPY rallies to $800+ (breakout) | Full $199.50 max loss (both legs expire worthless if SPY >> $787) | Acceptable per thesis (consolidation view). Close if SPY breaks $790 on volume — the pin thesis is broken. |
| SPY drops to $740 (correction) | Full $199.50 max loss (short leg deep ITM, long leg has intrinsic but debit lost) | Close if SPY breaks $750 — the pin thesis is broken. The calendar is not a hedge; it's a range trade. |
| Vol expansion (VIX spike to 25+) | Calendar benefits from vol expansion (long vega) — but if SPY moves with the vol, the pin is broken | Net vega is positive (~+$0.50/contract per 1% IV). Vol expansion helps the calendar if SPY stays in range. |
| Vol contraction (VIX drops to 12) | Calendar loses from vol contraction (long vega) — time value compresses on both legs | Manageable. The calendar's primary P/L driver is theta decay differential, not vol. |
| Time decay (theta) | Net theta is negative (~-$2-3/day) — the calendar loses time value daily | This is the cost of the trade. The harvest comes from the short leg decaying faster than the long leg. If SPY pins, the net theta turns positive as Oct 16 approaches. |
| Liquidity (SPY is the most liquid options market) | Both legs bid/ask ~$0.05-0.10 (~$0.15 round-trip cost on $199.50 debit = 0.08%) | Extremely liquid. No scale concerns at any reasonable size. |
| Early assignment on short 760P (European-style) | No early assignment risk — SPY options are European-style, cash-settled | N/A — European-style eliminates assignment risk entirely. |
Position Payoff at Two Horizons
The chart above shows the position's P/L as a function of SPY's price at two evaluation windows: now (entry, 66 DTE on short leg) and at Oct 16 (short leg expiry, 14 DTE remaining on long leg). The calendar's payoff is a "tent" shape — peak profit at the $760 strike on Oct 16, declining on both sides.
Read the chart:
- Spot $771.91 sits $11.91 above the $760 strike. At the current spot, the position is showing roughly +$50-$100 P/L per contract on the now-curve (66 DTE) — the short leg has $11.91 of intrinsic + time value, the long leg has $11.91 of intrinsic + more time value, minus the $1.995 debit. At Oct 16 at the current spot ($771.91), the position shows ~$260.50 modeled profit (short leg expires with $0 intrinsic if SPY > $760, long leg retains ~$4.60 of time value).
- The peak profit (~$685.63) sits at SPY ≈ $760 on Oct 16 — the short leg expires worthless (max time-value harvest), the long leg retains ~$8.85 of time value (14 DTE remaining, ATM).
- The modeled breakevens (~$758 and ~$787) are where the calendar's P/L crosses zero on Oct 16. Below $758, the short leg has intrinsic value that offsets the long leg's time value. Above $787, both legs are OTM and the debit is lost.
- The max loss ($199.50) is hit if SPY is far from $760 on Oct 16 (either direction) — both legs expire worthless or the intrinsic differential wipes out the time-value harvest.
Calendar asymmetry: Unlike a vertical spread (where the payoff is linear between strikes), the calendar's payoff is non-linear — it peaks at the strike and decays on both sides. The trade is profitable if SPY finishes between ~$758 and ~$787 on Oct 16 (~30% BSM probability); it loses if SPY moves outside that zone.
Position Specs
Trade: SPY Oct 16 / Oct 30 '26 760 Calendar Put Spread (66 DTE short / 80 DTE long) Instrument: SPY options (Oct 16, 2026 standard monthly short leg; Oct 30, 2026 standard Friday long leg; both 760P) Underlying: SPY (SPDR S&P 500 ETF; European-style, cash-settled, 1× SPY contract = 100 shares) Structure: Calendar Put Spread — 2 legs, same strike, different expiries Strike: $760 (both legs) Leg 1 (SHORT): STO −1× SPY 760P Oct 16, 2026 @ $12.775 (OptionStrat basis, 66 DTE) Leg 2 (LONG): BTO +1× SPY 760P Oct 30, 2026 @ $14.77 (OptionStrat basis, 80 DTE) Calendar span: 14 days (Oct 16 → Oct 30) Expiration (short): 2026-10-16 (66 DTE at entry, standard monthly) Expiration (long): 2026-10-30 (80 DTE at entry, standard Friday) Settlement: European-style, cash-settled. No early assignment risk on either leg. Net debit at fill: $1.995/share = $199.50/contract (OptionStrat basis) BSM cross-check: Within 2.2% of basis (acceptable) Implied IV (BSM solve from basis): ~16% (low-vol regime; SPY at all-time highs, VIX 15.45) Contracts: 1 calendar put spread Total debit: $199.50 (1 × $199.50) Peak modeled profit: ~$685.63/contract at SPY ≈ $760 on Oct 16 (short leg expires worthless, long leg retains ~$8.85 time value) Modeled profit at spot: ~$260.50/contract if SPY pins $771.91 on Oct 16 Max loss: $199.50/contract (= net debit, defined risk; hit if SPY far from $760 on Oct 16) Modeled breakevens (Oct 16): ~$758 (lower) and ~$787 (upper) Reward:risk (modeled): ~3.44:1 ($685.63 peak / $199.50 max loss — typical calendar asymmetry) Cushion to short strike: SPY at $771.91 is $11.91 above $760 strike (1.55% OTM on put side) P(pin) (BSM): ~30% (P($758 < SPY < $787) at σ=16%, T=66/365, S=$771.91) IV at entry: ~16% (BSM solve from basis; low-vol regime) Net delta (structure): Slightly negative (~−0.05/share) — modestly bearish bias at entry (put calendar below spot) Net gamma (structure): Positive — calendar benefits from SPY pinning near $760 (gamma peaks at strike) Net theta (structure): Negative (~−$2-3/day) — calendar loses time value daily; harvest comes from short leg decaying faster Net vega (structure): Positive (~+$0.50/contract per 1% IV) — calendar benefits from vol expansion Entry time: Aug 11, 2026 (OptionStrat save timestamp; afternoon save) Management rule: 50% of peak modeled profit (~$343/contract to close) OR close 7 DTE before Oct 16 if SPY outside $755-$790 Stop loss: 1.5× debit stop ($299/contract cost to close) OR SPY closes below $740 or above $800 before Oct 1 Position size note: Max loss $199.50 = 0.07% of $300k NLV — under the 0.25% per-trade guideline and well under the $5,000 absolute cap
Greeks Snapshot (Black-Scholes at entry)
| Greek | Per-contract value | Interpretation |
|---|---|---|
| Delta (Δ) | ~−$5.00 | Slight net negative delta. Modestly bearish bias at entry (put calendar below spot). |
| Gamma (Γ) | Positive | Calendar benefits from SPY pinning near $760. Gamma peaks at the strike. |
| Theta (Θ) | ~−$2-3/day | Net negative theta — calendar loses time value daily. Harvest comes from short leg decaying faster than long leg. |
| Vega (ν) | ~+$0.50 per 1% IV | Positive vega — calendar benefits from vol expansion. |
| Rho (ρ) | Small negative | Minor rate sensitivity. Negligible for a 2-month calendar. |
Management Plan
Entry context: SPY closed Aug 11 at $771.91, near all-time highs, with VIX 15.45 (low-vol regime). The 66-day front-month put IV at the 760 strike (~16% BSM solve) reflects low index vol — typical for SPY at highs with no major catalyst. Fed is in a data-dependent hold; Q3 earnings largely behind.
Entry signal: At ~1:00 PM ET on Aug 11, the desk checked the OptionStrat chain at the $760 put strike for Oct 16 / Oct 30. The basis prices were $12.775 (short) and $14.77 (long), netting $1.995 debit. The implied vol surface gave ~16% on both legs — within the BSM solve tolerance.
Execution: Both legs entered simultaneously via the OptionStrat strategy builder at the basis prices. Slippage minimal — SPY options are the most liquid in the world.
| Trigger | Action |
|---|---|
| 50% of peak modeled profit (~$343/contract to close) | Close the trade. Lock in half the potential harvest; remaining premium has lower risk-adjusted return. |
| SPY pins $760-$770 through Oct 10 | Hold; the calendar is working. Consider taking profit at 50% if offered. |
| SPY breaks above $790 or below $750 before Oct 1 | Close at market. The pin thesis is broken. |
| 7 DTE before Oct 16 (Oct 9) with SPY outside $755-$790 | Close at market. The harvest window is closing. |
| 1.5× debit stop ($299/contract cost to close) | Hard stop. The trade is no longer a defined-risk position. |
| Pre-FOMC Sep 16-17 | Decision point: hold through FOMC if expecting dovish hold (SPY-positive, pin-friendly) OR close before FOMC to avoid gap risk. |
Lessons
Pending — to be added after the trade closes. Pending observations at publication: how SPY behaves through the Sep 16-17 FOMC, whether the $760-$780 pin thesis plays out, and what the actual harvest looks like vs the $685.63 modeled peak.
— No lessons recorded yet. Trade still open at publication.
Position Update Log
| Date | SPY Close | Position Value | Unrealized P/L | Notes |
|---|---|---|---|---|
| 2026-08-11 (entry) | $771.91 | −$199.50 | — | Opened at OptionStrat basis. Spot $11.91 above $760 strike (1.55% OTM put side). BSM solve σ~16%. |
— No updates yet. Entry: Aug 11, 2026.
Disclosure
The desk may hold the positions, options, or underlyings mentioned in a trade-log entry at the time of publication; positions are disclosed in the trade-log entry itself. Nothing on this site is investment advice.
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