Notable Thursday Option Activity: AAP, KMX, RDDT

CarMax (KMX) saw unusually large options activity today with 33,632 contracts traded (~3.4 million underlying shares), equal to about 88.5% of its one‑month average daily volume; the $40 put expiring Dec. 19, 2025 accounted for 10,475 contracts (~1.0 million shares). Reddit (RDDT) recorded 38,513 contracts (~3.9 million underlying shares), roughly 87.9% of its one‑month average daily volume, led by 1,966 contracts (~196,600 shares) in the $242.50 call expiring Dec. 19, 2025. The outsized flows suggest concentrated positioning and potential for elevated short‑term volatility or liquidity effects in both names rather than fundamental corporate news.

Analysis

Market structure: The asymmetric options flow — ~10,475 KMX $40 puts (≈1.0M shares) vs ~1,966 RDDT $242.50 calls (≈196.6k shares) — signals concentrated directional positioning into Dec 19, 2025. That magnitude (KMX puts ≈88% of daily ADV in option-equivalent shares) can create pronounced dealer hedging flows and localized liquidity squeezes in KMX equity and implied-volatility skew; beneficiaries are liquidity providers and active option buyers, losers are passive long-equity holders if hedging pressure persists.

Risk assessment: Tail risks include a sharp consumer-credit shock (↑auto loan rates/bad debt) that would materially impair KMX revenue within 3–12 months, and an advertising pullback or content/regulatory shock that dents RDDT monetization. Immediate (days) risk is elevated intraday volatility; short-term (weeks–months) risk is option unwind and IV repricing; long-term (quarters) fundamentals (used-car cycle for KMX, ad/engagement for RDDT) dominate. Watch hidden dependencies: borrow costs, short interest, and market-maker delta hedging sensitivity to >$5–10 moves.

Trade implications: Tactical plays: express bearish KMX with limited-risk put spreads (Dec19’25 40/35 put spread) size 1–2% portfolio risk; express bullish RDDT with bull-call spread (Dec19’25 200/260) or 1–3% outright equity, scaling on pullbacks >5%. Pair trade: long RDDT / short KMX (1:1 dollar) to isolate market beta. Time entries around earnings and Fed/CPI windows; prefer initiating on IV contraction of ≥10% from current levels.

Contrarian angles: Heavy KMX put volume could be portfolio hedges or structured trades, not pure bearish bets — downside may be overstated if used-car supply normalizes. Historical parallels: cyclical auto sell-offs often mean-revert over 6–12 months once credit stabilizes. Unintended consequence: crowded positioning could flip into a squeeze if retail buys KMX on any positive catalyst; monitor borrow rates >5% and options OI change >30% week-over-week.

Key Decisions for Investors

• Establish a limited-risk bearish position in KMX: buy Dec 19, 2025 40/35 put spread (1x contract per $50k notional) sizing to 1–2% portfolio risk; add if KMX prints below $40 with >3% daily move and IV rises >20% intraday.
• Establish a bullish stance in RDDT: enter Dec 19, 2025 200/260 bull-call spread (debit) sized to 1–3% of portfolio, target 40–80% upside by expiry; scale in on any pullback >5% or post-earnings dip.
• Implement a relative-value pair: go long RDDT equity or calls and short KMX equity in dollar-neutral amounts equal to 0.5–1% each to capture dispersion; rebalance if divergence exceeds 15% or correlation breakdown persists >30 trading days.
• Monitor three triggers before adding size: KMX borrow rate moving above 4–5%, weekly options OI in KMX rising >30%, or upcoming KMX quarterly results showing sequential deterioration in used-car gross margins — each should prompt +50% sizing increase.