Ratio Call Write Strategy in Indian Markets: Margin, Payoff and Assignment Maths

What A Ratio Call Write Actually Is

A ratio call write is built from two pieces. First you own the underlying, either the cash shares or a long futures position. Second you sell call options against it, but you sell more calls than your holding covers. The classic version is the 2:1 ratio call write: you hold one lot worth of the underlying and sell two calls of the same strike and expiry. One of those calls is genuinely covered by your stock. The second is naked, meaning there is nothing behind it if the price runs higher.

That extra short call is the whole point and also the whole danger. It hands you a second slice of premium, which lowers your breakeven and pads your income in a sideways market. But a naked short call has theoretically unlimited loss because a stock can keep rising. So a ratio call write is not a gentle income trade like a plain covered call. It is a neutral to mildly bearish position with a capped reward and an open-ended risk on the upside, and it must be margined and managed as such.

The previous version of this page suggested owning 100 shares and selling 150 calls, as if Indian options trade in odd share counts. They do not. On the NSE every F&O contract trades in a fixed lot size. You cannot sell 1.5 contracts. The real Indian version of this strategy is built in whole lots, for example hold one lot of stock futures and sell two lots of calls. The numbers below are reworked on that correct basis.

Covered Call Versus Ratio Call Write

It helps to see the ratio call write next to the plain covered call it is derived from. In a covered call your short calls are fully backed by stock, so your only real risk is opportunity cost if the stock rockets past the strike. In a ratio call write the uncovered call removes that safety and replaces it with genuine, uncapped downside.

The takeaway from the table is that the ratio call write is not a beefed up covered call. It is a different risk animal. You are trading away your upside protection for extra premium, and the broker will demand margin on the naked leg to reflect that.

Worked Example: Reliance 2:1 Ratio Call Write

All numbers below are illustrative and rounded for teaching. Reliance Industries has an F&O lot size of 500 shares. Assume Reliance is trading at Rs 1,200. You are mildly bearish to neutral for the next few weeks and want premium income. You set up a 2:1 ratio call write on the monthly expiry.

• Long leg: buy 1 lot of Reliance futures at Rs 1,200. That is exposure to 500 shares, notional Rs 6,00,000.
• Short leg: sell 2 lots of the Reliance 1,250 call at a premium of Rs 20 each. That is 2 x 500 = 1,000 call units.
• One of those call lots is covered by your long future. The second lot is the NAKED call, the source of both your extra income and your tail risk.

Premium collected up front: Rs 20 x 1,000 units = Rs 20,000. That cash hits your account immediately. Your job now is to keep as much of it as possible, which happens only if Reliance stays at or below roughly the 1,250 strike by expiry.

The Payoff Diagram In Numbers

A real payoff diagram for a ratio call write has a distinctive tent shape. Profit rises as the stock climbs toward the short strike, peaks at the strike, then falls away on the other side as the naked call starts losing faster than the long future gains. The table below is that diagram expressed as rupees of profit and loss at expiry for our Reliance trade, ignoring costs for clarity. Read it top to bottom and you can see the tent.

Notice the structure. Maximum profit is Rs 45,000 and it sits at the 1,250 strike, where the long future has gained Rs 25,000 and both calls still expire worthless so you keep the Rs 20,000 premium. Move below the strike and your long future loses money, eating into the premium. Move far above the strike and the naked call losses overwhelm everything. There is a lower breakeven near 1,160 where the future loss equals the premium, and an upper breakeven near 1,375 where the naked call loss equals the peak profit. Above 1,375 the position bleeds without limit.

Margin Maths: What You Must Actually Park

This is where the previous page was silent and where most beginners get hurt. The Rs 20,000 premium does not fund the trade. The NSE clearing system charges SPAN plus exposure margin on the net position. Your long future and the one covered call partly offset, but the second, naked short call is treated as an outright short option and carries heavy margin, especially as it moves toward the money.

• Long 1 lot Reliance future: roughly Rs 1,00,000 to Rs 1,20,000 of SPAN plus exposure margin at a 1,200 price and a notional of Rs 6,00,000 (illustrative, margins change daily with volatility).
• Short 2 lots of the 1,250 call: the covered lot is partly offset by the future, but the naked lot can demand Rs 60,000 to Rs 1,00,000 or more depending on how close to the money it is and the prevailing volatility.
• Total blocked margin can realistically be Rs 1,80,000 to Rs 2,50,000 to collect Rs 20,000 of premium. Your return on margin, not on premium, is what matters.

Two further margin facts are non negotiable in India. First, SEBI enforces upfront margin collection and peak margin rules, so the full margin must be available before you take the trade. Second, margin on a short option is marked to market and recalculated as the underlying moves. If Reliance gaps up toward 1,250, the margin on your naked call balloons and your broker can issue an intraday margin call or square off the position. A ratio call write that looked comfortable on Monday can demand far more cash on Wednesday after a rally.

Assignment Maths On The Naked Call

Indian index options (Nifty, Bank Nifty, FinNifty, Sensex) are cash settled, so there is no delivery, only a cash debit or credit at expiry. Single stock options like Reliance, however, are physically settled. If your short Reliance calls are in the money at expiry, you are assigned and you must deliver shares. This is the part that surprises traders and it is exactly why a naked leg is dangerous.

Walk it through at an expiry price of 1,330. Both your 1,250 calls finish in the money, so you are assigned on 2 lots, that is an obligation to deliver 1,000 Reliance shares at 1,250. Your long future delivers into one lot, covering 500 shares. The second lot has no shares behind it. You must either buy 500 shares in the cash market near 1,330 to deliver at 1,250, locking a Rs 80 per share loss on that leg, or square off the option before expiry. Either way the naked lot costs you, and physical settlement also brings higher delivery margins in the expiry week.

• Covered lot at 1,330: long future delivers 500 shares into the assignment, clean.
• Naked lot at 1,330: you owe 500 shares at 1,250 but the market is at 1,330, a Rs 80 x 500 = Rs 40,000 hit on that leg before premium.
• Net of the Rs 20,000 premium and the future gain, this matches the Rs 25,000 profit line in the payoff table, which shows the assignment cost is already baked into the diagram.
• To avoid physical delivery entirely, square off both short calls before the expiry day close. Most retail traders should never let a short stock option go to physical settlement unless they want the delivery.

Costs: Brokerage, STT And The Real Net

Premium and payoff are gross numbers. Indian transaction costs are small per trade but they are real and they always reduce your edge. For options, STT is 0.1 percent on the sell side of the premium. On our Rs 20,000 of premium that is about Rs 20. Far more important is the STT trap on assignment. If a short option is exercised or assigned, STT is 0.125 percent of the intrinsic settlement value, calculated on the strike based settlement, which is much larger than the premium based STT. Letting an in the money short option expire and get assigned is therefore costlier than squaring it off, another reason to close before expiry.

For a single discretionary trade these costs are minor against a Rs 45,000 peak or a five figure loss. But if you run ratio writes repeatedly, the assignment STT and per leg brokerage compound, so a disciplined trader squares off rich short options rather than carrying them into settlement.

Entry, Adjustment And Exit Rules

Enter only when your view is genuinely neutral to mildly bearish and ideally when implied volatility is elevated, because you are a net seller of options and richer premium widens your breakevens. Selling cheap options in a dead, low volatility tape gives you thin premium for the same uncapped risk, which is a poor trade.

• Entry: choose a strike above the current price, often near a resistance level you expect to hold, and confirm the option is liquid with tight bid ask spreads.
• Sizing: keep the naked leg small relative to your capital. One extra short lot per one covered lot is already aggressive. Never scale the ratio to 3:1 or 4:1 chasing premium.
• Adjustment: if the underlying rallies toward your strike, roll the naked call up and out to a higher strike and later expiry, or buy a further out call to convert the naked leg into a defined risk call ratio spread.
• Hard exit: define a price, for example the short strike itself, at which you buy back the calls no matter what. Above the strike your loss accelerates, so discipline at this line is what separates a managed trade from a blow up.
• Time exit: take profit early. If you have captured 60 to 70 percent of the premium with time still left, close it. The last bit of premium is rarely worth the open ended risk of holding into expiry.

Defined Risk Alternative: The Call Ratio Spread

If the unlimited upside of a true ratio call write is too much risk, and for most retail traders it is, you can cap it. Instead of leaving the extra call naked, buy a higher strike call against it. This turns the position into a call ratio spread with a hard ceiling on losses. You give up a little premium to buy that insurance, but you sleep at night and your margin drops sharply because the long call defines the risk.

On the Reliance example you might keep the long future and the two short 1,250 calls, then buy one 1,300 call for a small debit. Now the runaway loss above 1,375 is capped, because beyond 1,300 your bought call gains alongside the naked short. The trade still collects net premium and still profits in a flat to mildly bearish tape, but the catastrophic tail is gone. For anyone not running a professional risk desk, the defined risk version is almost always the smarter way to express this idea on Indian single stocks.

Tax Treatment In India

Profit or loss from F&O, including this ratio call write, is treated as non speculative business income under Indian tax law, not as capital gains. That means the STCG rate of 20 percent and the LTCG rate of 12.5 percent above Rs 1.25 lakh do not apply to your options profit. Instead the net business profit is added to your total income and taxed at your applicable slab rate. The flip side is favourable: F&O losses can be set off against other non speculative income and carried forward for up to eight years if you file your return on time.

Because it is business income, you can deduct genuine trading expenses such as brokerage, exchange charges, advisory fees, and a reasonable share of internet and platform costs. Keep clean records of every leg, premium, and cost. Where turnover crosses the prescribed thresholds a tax audit may be required, so a ratio writer who trades actively should plan for proper bookkeeping. This is general information, not personal tax advice, so confirm your own position with a qualified chartered accountant.

Common Mistakes And How To Avoid Them

• Treating it like a covered call. The naked leg has unlimited risk and must be margined and watched as a short option, never assumed safe.
• Sizing on premium instead of margin. You collected Rs 20,000 but blocked over Rs 1,80,000. Always size against worst case margin, not the cash received.
• Ignoring physical settlement. Single stock options deliver shares. Letting an in the money short stock call expire can force a delivery and a heavy assignment STT. Square off before expiry.
• Selling into low volatility. Thin premium for uncapped risk is a bad bargain. Prefer elevated implied volatility.
• No hard exit above the strike. Without a pre set buy back level, a gap up turns a small loss into a portfolio sized one before you react.
• Over ratioing. Stretching to 3:1 or 4:1 multiplies the naked risk far faster than it grows the premium.

Sources And Further Reading

Always confirm current contract specifications, lot sizes, margins, STT rates and tax rules on the official source before you trade, because the NSE revises lot sizes and SEBI revises margin rules periodically. Useful references include the NSE Option Chain for live strikes and premiums, the Income Tax Department for tax treatment, and Zerodha Varsity for options mechanics and margin explanations.

Sources and Further Reading

For authoritative data and further reading on this topic, refer to NSE Option Chain, Income Tax Department and Zerodha Varsity. Always confirm current rules, rates and contract specifications on the official source before you trade.