MRVL stock | How to short MRVL stock? | Mrvl stock, Nov 2 open price, 191, I knew that mrvl will go down 10%,no bear ETF, how to use option to short mrvl 100 shares?

 Good lesson question — and Nov 2 is closed tape, so we can work the math on it. This is the short module you don't have yet, designed on a calm day, which is exactly how it should be built.

**Your setup, as you stated it**
- MRVL open Nov 2: **$191**
- Your target move: **−10% → ~$171.90** (it actually closed $171.41 that day, −10.3% from that open — the tape proved it, but at the open that was a prediction, principle 4: 不预测，只反应）

**The option equivalent of shorting 100 shares: buy 1 put contract**
- 1 contract = 100 shares. That's your whole size — 1 contract, not 2 or 3.
- At Questrade: *Buy to Open* 1 put, and later *Sell to Close* it at the screen. You almost never exercise — exercising would create an actual short stock position.

**Strike choice = how closely it tracks a short**
- **ATM, $190 put:** delta about −0.50 at entry. First $1 drop only makes you ~$50, not $100. As price falls, delta moves toward −1.00 and it starts tracking share-for-share.
- **ITM, e.g. $200 put:** delta about −0.70 to −0.80, tracks a short much sooner — but costs more premium.
- **OTM, e.g. $180 put:** cheap, delta about −0.30. Usually a lottery ticket — direction can be right and it still loses.

**The math at your target** (illustrative — I don't have the actual Nov 2 put premium on record, so premium stays a variable):
- $190 put, MRVL at $171.90 → intrinsic value = $190 − $171.90 = **$18.10/share = $1,810 per contract**
- Your profit = $1,810 − premium paid
- Breakeven = strike − premium. If the premium had been $8.00/share ($800 for the contract), breakeven is $182, and max loss is that $800, period — even if MRVL goes up. That premium *is* your fixed dollar risk, principle 6.

**Two other structures, for completeness**
- *Bear put spread* (buy $190 put, sell $170 put): cheaper, less time-decay, but gains capped at the $20 width — mathematically it fits a defined "−10% and stop" target, at the cost of a second leg.
- *Synthetic short* (buy put + sell call, same strike): tracks 1:1 like stock, but the sold call carries large, open-ended risk. Not the clean version for you.

**Written before entry, same as your long system:** strike, expiry (must cover your time window — same-week expiry is cheap but theta eats you if you're a day early), premium = max loss, and the manual exit: sell to close into your target zone, or out when the setup is invalidated.

If you want this kept as a short-module candidate, give me the three blanks in your words: entry motivation (what chart trigger, not "I knew"), the max premium you'd risk per trade, and the manual take-profit target.