Double Calendar

Strategy 3 — Double Calendar Straddle

Current Mode: DRY-RUNDC_DRY_RUN = True. Scanner fires and positions are tracked with simulated fills, but no real orders are placed. Switch to live by setting DC_DRY_RUN = False in config.py.

How it works

A Double Calendar executes two simultaneous ATM straddles on the same underlying (NIFTY) and same strike, but different expiries: it SELLS the near-expiry (weekly Tuesday) straddle to collect fast-decaying Theta, and BUYS the far-expiry (last Tuesday of month) straddle to hedge Vega risk and cap maximum loss.

This is a Vega-long, Theta-neutral strategy. P&L is driven primarily by IV levels, not by how far spot moves. The current entry band is near IV 15–25% (elevated enough for premium, but not event-risk territory), so that theta front-loading on the near leg exceeds the far leg's premium cost. Entry creates a small net debit; the profit target is 32% of that debit, net of all transaction costs.

SELL
CE (Near, Weekly)
₹145
+ ₹145
SELL
PE (Near, Weekly)
₹130
+ ₹130
BUY
CE (Far, Monthly)
₹290
− ₹290
BUY
PE (Far, Monthly)
₹280
− ₹280
Near Straddle Collected = 145 + 130 = ₹275 pts
Far Straddle Paid = 290 + 280 = ₹570 pts
Net Debit = 570 − 275 = ₹295 pts (₹19,175 for 65 lots)
Transaction costs (entry+close) ≈ ₹1,200–1,400 total
Profit Target (32% of debit) = 295 × 0.32 × 65 − costs = ≈ ₹4,740 net
Stop Loss (Trigger 1, −20% debit) = − 295 × 0.20 × 65 = −₹3,835

Entry Filters (all must pass)

FilterConfigWhy
DTE to near expiryDC_MIN_DTE=3 to DC_MAX_DTE=7Enough time for theta advantage; not so short that gamma dominates
Near ATM IV ≥ minDC_MIN_IV = 15%Enter only when near IV is high enough for the straddle premium to support the theta edge
Near ATM IV ≤ maxDC_MAX_IV = 25%Avoid event risk (results, RBI) — IV could explode and kill the short near leg
Far−Near IV gapDC_MAX_IV_SPREAD = 5%Skip if far expiry has event premium priced in (far IV much higher than near)
Near straddle premiumDC_MIN_NEAR_STRADDLE = 80 ptsEnough theta to collect to make the trade worthwhile
Controlled MDC scale-in90 min + meaningful move + healthy anchorA second DC-family position is considered only after a genuinely new market move; identical option legs are always rejected
Two slots do not mean duplicate sizing. MDC may hold up to two DC-family positions, but a second entry must be at least 90 minutes after the newest remaining MDC position and spot must move by at least max(200 points, 50% of the anchor near straddle). The anchor must remain OPEN, have live P&L available, and stay above a −10% loss threshold. MDC then reclassifies the market normally and may choose any eligible DC-family structure. The executor rejects an exact repeat of the complete option security-ID set before dry-run simulation or broker orders.
Why an IV floor? At very low IV the straddle premium is structurally too low — theta decay on the near leg barely covers the far leg's time-value bleed. The configured floor is currently 15%, while the upper cap remains 25% to avoid event-risk entries. The spot-based 2.5% stop was removed because DC P&L is driven more by IV and debit behavior than raw spot distance.

Expiry Selection Logic

get_expiries() ├── near = next Tuesday after today (NIFTY weekly expiry) ├── dte = (near − today).days │ └── not in [DC_MIN_DTE, DC_MAX_DTE] → return None (no trade today) └── far = last Tuesday of near's month └── if (far − near).days < 7 → last week of month → use NEXT month's last Tuesday └── e.g. if near = Apr 22, far would be Apr 29 (only 7d gap) → use May 27 instead

P&L Calculator + Theta Advantage Simulator

Adjust the inputs to model your trade. The time slider shows how theta decay affects each leg. Profit target is 32% of net debit; three stop triggers shown below.

Near straddle (SELL)
₹275 pts
₹17,875 collected
Far straddle (BUY)
₹570 pts
₹37,050 paid
Net Debit
₹295 pts
₹19,175 max risk
Profit Target (32% debit)
₹94 pts
₹6,136 net
P&L Stop (−20% debit)
−₹59 pts
−₹3,835 trigger
Risk/Reward
1 : 1.60
Target / P&L Stop
Near Straddle Current Value
₹275
P&L on short: ₹0
Far Straddle Current Value
₹570
P&L on long: ₹0
Net P&L (points × lots)
₹0
Target: ₹6,136
Position P&L: ₹0
*Theta decay approximated as √DTE ratio (constant IV). Actual path depends on realized volatility and IV levels.