STBT Trading
STBT — Sell Today, Buy Tomorrow — is the mirror image of BTST. You sell first, then buy back the next day to close the position. Because Indian cash equity does not allow overnight short positions, STBT primarily lives in the futures and options segment, where short selling is legitimate and can be carried overnight.
Key takeaways:
- STBT is selling first and buying back the next trading day, used to profit from falling prices.
- Pure cash-market STBT is not allowed for retail investors in India — short positions must be closed the same day.
- In F&O, you can sell a future or write an option today and square off tomorrow under NRML.
- Margins are calculated on the full SPAN + Exposure for any overnight short.
- Overnight news risk is amplified for shorts because a single gap-up can wipe out weeks of gains.
Why STBT is mostly an F&O concept
In Indian cash equity, you cannot deliver shares you do not own. SEBI’s short-selling framework allows institutional Securities Lending and Borrowing (SLB), but retail traders cannot carry naked equity shorts overnight. Any short sold under MIS must be bought back the same day. STBT in cash equity is therefore restricted to securities you have borrowed via SLB, which is rare for retail.
F&O removes this constraint. Futures and options are contracts, not deliverable securities (until expiry), so you can sell a future or write an option overnight without owning anything in advance. STBT thrives here.
How a typical STBT trade works in F&O
- You expect Bank Nifty to fall on weak global cues and US Fed commentary overnight.
- At 3:25 p.m. you sell one lot of Bank Nifty futures at 48,200 under NRML.
- The required SPAN + Exposure margin is blocked.
- Next morning, Bank Nifty opens at 47,800 on bearish cues.
- You buy back at 47,800, locking in a 400-point profit before charges.
Risk profile of STBT
STBT looks symmetrical to BTST, but the risks are not. A long position has limited downside (price cannot fall below zero) and unlimited upside. A short has limited upside (price cannot fall below zero) and theoretically unlimited downside. A surprise positive news event — a tax cut, a rate pause, a buyback — can spike the underlying overnight and create heavy losses on a short carried overnight.
Margin and MTM rules
Because short positions are riskier, the exchange charges the full margin under NRML. The position is marked to market every evening. If losses eat into your margin, the broker will issue an MTM call and may square off the position the next morning before you act.
Some brokers also keep an additional overnight margin buffer for option writers because options can gap aggressively on news.
When traders use STBT
- Hedging long delivery portfolios against expected overnight bad news.
- Trading around known events — central bank meetings, results, GDP data.
- Selling rich-priced options to capture overnight theta decay.
- Pair trading: short the weaker index/stock future and long the stronger one.
STBT in cash equity — what is and is not allowed
SLB-based STBT is technically possible: you borrow shares from a lender via the exchange’s SLB platform, sell them today, and return them tomorrow by buying back. This is operationally heavy and not common among retail traders. For most practical purposes, when an Indian trader says STBT they mean F&O.
Frequently asked questions
Is plain short selling allowed overnight in cash equity?
No. Retail traders can only short intraday under MIS. Overnight shorts in cash equity require SLB borrowing.
Can I do STBT in stock options?
Yes — you can sell (write) a call or put today and buy it back tomorrow under NRML, subject to margin requirements.
What about physical settlement risk?
If you let a short stock-future or in-the-money option get to expiry, you must deliver shares. STBT trades are usually closed well before expiry to avoid this.
How do losses compare to BTST?
Losses from a short can grow faster than from a long because there is no upper price cap. Strict stop losses are essential for STBT.
