Studying for the CFOA exam and went down a rabbit hole on short strangle delta
u/FinCosmos ·
Reddit — r/options
· May 27, 2026 at 12:21
· ⬆ 8 pts
· 💬 11 comments
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Summary
The thread focuses on the mechanics of short strangles during an IV spike, specifically how net delta remains near zero but gamma and vega exposures change.
Dominant sentiment is analytical/theoretical, not directional; no specific stocks, indices, or earnings are discussed.
Consensus: both top comments agree that after a large IV spike, the position becomes a long IV mean-reversion bet rather than a pure theta carry trade.
Score8
Comments11
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[+6] u/ThetaEdgeHQ: Your first instinct on net delta is actually correct on the narrow point. The other thing the comments are circling but not quite landing on is what the actual position state looks like after that 40 percent IV spike.
Net delta stays approximately zero. Both wings shift toward higher delta in absolute value (a 16 delta call at the original IV becomes maybe a 22 to 25 delta call at the new IV at the same strike), but the position is balanced so they offset. Your first instinct holds on that piece.
What actually changed:
Vega P&L. A 30 DTE 16 delta strangle with a 40 percent IV spike loses roughly 1.5 to 2 times the original credit on mark to market. The credit is gone and the position is meaningfully underwater immediately.
Gamma per leg. Each wing now sits at higher absolute delta with higher gamma. The position is still net delta neutral but reacts faster to spot moves than it did 24 hours ago. Net delta stays neutral only as long as spot does not trend.
IV mean reversion is now the trade. If spot stays flat and IV mean reverts back toward 30 over the next 30 days, the strangle profits significantly faster than from theta decay alone, recovering the vega loss plus the original credit. If you think the IV regime has reset to a new higher baseline, the position is structurally damaged and there is no recovery path from spot staying flat.
The exam answer is probably some compressed version of the first paragraph. The actual trader answer is that the position is now a long IV mean reversion bet stapled to a delta neutral structure, not the theta carry trade it was the day before.
[+6] u/Aggressive_Deer_7072: Your brother is probably right honestly. if IV explodes the position doesnt stay perfectly neutral even if both strikes remain OTM.
The deltas of both options can expand asymmetrically because higher vol increases probability of touching/moving ITM. plus skew/vanna effects start mattering during big macro vol shocks. short strangles can suddenly pick up directional exposure even without spot moving much. thats kinda the nasty part lol