Options Trading
A master reference page for options-trading concepts: the instrument itself, how the market prices it, the Greeks that move premium, trade-management discipline, and defined-risk spread structures. Written in plain-English, oriented toward Indian index and equity options (NIFTY, single-stock F&O) but the mechanics generalise.
1. The instrument
Call (CE) — the right, not the obligation, to buy the underlying at a fixed strike price on or before expiry, in exchange for paying a premium upfront. You buy a call when you’re directionally bullish. Max loss as a buyer is the premium; upside is theoretically unbounded.
Put (PE) — the mirror right: to sell the underlying at the strike. Bought when bearish. Max loss as a buyer is again the premium.
Strike price — the contractual exercise price baked into the option. Embedded in the ticker itself (e.g. NIFTY26MAY25000CE → strike 25,000).
Expiry — the last day the option is alive. Indian monthly index options expire on the last Thursday of the month. If the underlying doesn’t move enough in your direction by expiry, an out-of-the-money option decays to zero and dies worthless.
Premium — the market price of the option itself. The buyer pays it; the seller receives it. Premium has two components: intrinsic value (the portion already “in the money”) and extrinsic value (time + volatility — everything else).
Lot size — options trade in fixed lot quantities, not single shares. NIFTY = 75 shares/lot (post the late-2024 revision from 50); individual stocks vary by symbol. Exposure is always lot-multiple; a single lot of NIFTY at ₹100 premium = ₹7,500 of premium risked.
Moneyness — ITM / ATM / OTM
| Term | Call | Put |
|---|---|---|
| In-the-money (ITM) | Strike below spot | Strike above spot |
| At-the-money (ATM) | Strike ≈ spot | Strike ≈ spot |
| Out-of-the-money (OTM) | Strike above spot | Strike below spot |
ITM options have intrinsic value and are expensive. OTM options are pure extrinsic (time + vol), cheap, but require the underlying to actually move your way to pay off. ATM options sit between — highest extrinsic, highest gamma, most responsive to small moves.
2. Reading the market
India VIX and implied volatility
India VIX is an index that measures the market’s forward-looking fear/greed by distilling it from option prices. A high VIX means options are pricing in big moves; a low VIX means complacency.
| VIX band | Regime |
|---|---|
| < 12 | Very calm. Premiums cheap. |
| 14–18 | Normal. |
| 20+ | Nervous. |
| 26+ | Panic. Premiums extremely fat. |
Rule of thumb: high VIX = good to sell premium, bad to buy. Low VIX = flip. Buying calls during a VIX spike means over-paying; even if direction is right, the subsequent vol-crush eats into profit (the “IV crush” pattern post-event).
Implied volatility (IV) is the per-option version: the specific vol the market is pricing into this strike and expiry. VIX is the aggregate; IV is the local. When VIX is 26, individual IVs are also elevated.
Mean reversion and moving averages
200-DMA (200-day moving average) and 50-DMA are smoothed “fair value” anchors. Price well below 200-DMA suggests the market has been beaten up and mean-reversion is plausible; well above, pullback risk. These aren’t predictors, they’re reference levels.
RSI (Relative Strength Index) puts a number on “too far too fast”: RSI < 30 is conventionally oversold, RSI > 70 overbought.
Support and resistance
Support is a price level buyers have reliably shown up at; resistance is where sellers have. They’re used for both entry (buy near support, sell near resistance) and for selecting strikes in spreads — sell premium beyond strong S/R, buy directional options toward them.
3. The Greeks
Four dials that move every option’s price. Think of them as sensitivities — rate of change with respect to a given input.
Delta — option’s rupee move per ₹1 move in the underlying. Calls: 0 to +1. Puts: 0 to −1. Deep OTM options have tiny delta (0.10–0.20); ATM ≈ 0.50; deep ITM → 1. Delta also approximates the probability (under a log-normal model) that the option finishes ITM.
Theta — daily decay. Always negative for buyers, positive for sellers. Time is the seller’s ally and the buyer’s enemy. Theta accelerates non-linearly in the final 2–3 weeks before expiry; a far-dated option bleeds gently, a weekly hemorrhages. Picking farther expiries is how a directional buyer buys runway.
Gamma — the rate of change of delta. High gamma means P&L swings accelerate fast as the underlying moves. Peaks near ATM and near expiry. Short-dated ATM options are “explosive” — small moves produce outsized P&L. Beginners don’t need to hedge gamma actively, but should know that short-dated ATM positions behave very differently from long-dated OTM ones.
Vega — sensitivity to a 1-point change in IV (or equivalently VIX). Buyers are long vega (benefit when vol rises). Sellers are short vega (hurt when vol rises). Buying during high VIX and watching VIX collapse is the “IV crush” trap — direction can be right and you still lose money because vega worked against you.
Rho (sensitivity to interest rates) exists but is usually negligible at retail scale and over short holds; omitted here.
4. Managing the trade
Breakeven (at expiry) — for a long call, Strike + Premium paid. For a long put, Strike − Premium paid. Note: you don’t have to reach breakeven to profit if you exit before expiry — remaining extrinsic value can carry you into the green even if the underlying hasn’t crossed strike + premium yet.
Stop loss — a pre-decided exit price to cap damage. A common discipline for long options is exit if premium drops 50%. For premium sellers, stops are usually set on the underlying’s price rather than the option’s (because option premium can spike on IV shocks even when direction is intact).
Target / take profit — a pre-decided exit to book gains. A textbook zone for buyers is 2×–3× premium paid.
Position sizing — the amount of capital risked on any single trade. Conservative beginner rule: risk no more than 1–2% of total trading capital on one option bet, where “risk” = premium paid (for buyers) or maximum defined loss (for spread sellers). See kelly-criterion for the formal underpinning: the goal is to avoid ruin so compounding can occur.
Risk-Reward (R:R) — for each rupee of risk, how many of reward. Good option trades target 1:2 or better, which lets the math work even at 40–50% win rate.
Expected value (EV) — the weighted outcome across many trades:
EV = (Win probability × Average win) − (Loss probability × Average loss)
A strategy with a 50% win rate that wins ₹200 and loses ₹100 has EV = 0.5(200) − 0.5(100) = +₹50 per trade. Positive EV with disciplined sizing compounds; that’s the engine. Beginners typically over-weight win rate and under-weight EV — a 90%-winning strategy with rare but catastrophic losses is often negative-EV. See probability-theory for the formal framework.
5. Spreads and defined risk
A spread is simultaneously buying one option and selling another on the same underlying and expiry at different strikes. The point is to cap both cost and profit in exchange for defined risk. Spreads are the graduation path from buy-only trading to premium-selling without open-ended tail risk.
Bull call spread (debit, bullish)
- Buy 1 ATM or slightly OTM call.
- Sell 1 further-OTM call.
- Net cost = premium paid − premium received.
- Max profit = (difference between strikes) − net cost, realised if the underlying finishes ≥ the higher strike at expiry.
- Max loss = net cost.
Trade-off: you cap upside in exchange for a much cheaper directional bet. Ideal when you have a price target and want to stop paying for upside beyond it.
Bear put spread (debit, bearish)
- Buy 1 ATM or slightly OTM put.
- Sell 1 further-OTM put.
- Mirror of the bull call; same logic in the bearish direction.
Bull put spread (credit, mildly bullish)
- Sell 1 OTM put (collect premium).
- Buy 1 further-OTM put (pay a smaller premium — insurance).
- Keep the net credit if the underlying stays above the sold strike at expiry.
- Max loss = (strike difference) − net credit.
This is the defined-risk version of a naked short put. Whereas a naked short put has losses that scale linearly as the underlying falls (theoretically to zero on the underlying), the bull put spread caps them at the width of the spread minus the credit. Almost always the correct structure once a trader moves from “buy-only” to “sell premium.”
Bear call spread (credit, mildly bearish)
- Sell 1 OTM call, buy 1 further-OTM call.
- Profit if underlying stays below the short strike.
- The defined-risk version of a naked short call.
Iron condor (credit, range-bound thesis)
- Bull put spread + bear call spread on the same expiry, different strikes.
- Sell OTM put + buy further-OTM put (downside insurance).
- Sell OTM call + buy further-OTM call (upside insurance).
- Profit if the underlying stays within the range. Defined loss if it breaks out either side.
- Harder to manage dynamically; usually skipped until single-leg spreads are comfortable.
Debit vs credit — the strategic distinction
| Debit spread | Credit spread | |
|---|---|---|
| Cash flow at entry | You pay | You receive |
| Max loss | Premium paid | Strike width − credit |
| Time decay | Hurts you (you’re net long theta-bearing options) | Helps you (net short theta) |
| Best when | Directional thesis, options expensive (high IV) | Direction or range thesis, want theta tailwind |
Debit spreads are for directional bets when premium is rich — you’re paying for the move but capping cost. Credit spreads are for when you want time-decay to work for you without the tail risk of naked selling.
6. Risk-management principles
- Never trade naked short options unless you deeply understand tail-risk pricing and can bear the full potential loss. Gap-down events on earnings or macro surprises have bankrupted many otherwise-disciplined traders.
- Don’t buy premium during VIX spikes unless the directional edge is strong enough to absorb the subsequent IV crush.
- Pick enough time. Cheap weeklies look attractive but theta bleed is brutal. Give the thesis room.
- Size for survival, not maximisation. A trader who survives a decade compounds; one who blows up in year two doesn’t. See kelly-criterion.
- Plan the exit before entry. Target, stop, and time stop (close by date X regardless of P&L) should be decided before the trade is live.
- EV > win rate. A high-win-rate strategy with rare but catastrophic losers often has worse EV than a 45%-winner with tight risk control.
Connections
- kelly-criterion — the mathematical spine of position sizing; avoiding ruin is the precondition for positive-EV strategies to compound.
- probability-theory — expected value, distributions, variance; the formal language of option pricing and risk.
- bayes-theorem — Bayesian updating on new market information (earnings surprises, macro data) is the principled way to revise a thesis mid-trade.
- loss-aversion — buyers over-react to daily theta bleed; sellers under-react to tail risk; both are prospect-theoretic distortions of rational option management.
- prospect-theory — the psychology of asymmetric option payoffs maps directly onto Kahneman–Tversky value function shapes.
- mental-accounting — treating “premium collected” as free money is a classic mental-accounting error; all capital is fungible.
- sunk-cost-fallacy — averaging down on losing options because of what’s already invested, rather than current expected value, is the purest form of sunk-cost reasoning.
- first-principles-thinking — decomposing option price into intrinsic + (time-value + vol-value) and risk into delta/theta/gamma/vega is first-principles analysis of a derivative.
- inversion — “how would I guarantee losing money in options?” (sell naked during calm, buy during panic, oversize, fight the trend) generates most of the risk-management rulebook by negation.
- compound-interest — surviving to trade another day is what lets positive EV compound into meaningful wealth.
Sources
- source—options-glossary — plain-English glossary covering instrument basics, market reading, Greeks, trade management, and defined-risk spreads.