Contents
Definition
In derivatives markets, a lot size (also called contract size) is the number of underlying shares that one futures or options contract represents. An investor cannot trade fractions of a lot — if Nifty 50 has a lot size of 25 and the index is at 22,000, one contract has a notional value of 22,000 × 25 = ₹5,50,000. SEBI mandates that NSE and BSE review and revise lot sizes for all F&O contracts semi-annually (every six months) to maintain notional contract value within a target range of ₹5–10 lakh. As prices move, lot sizes are adjusted to keep contracts accessible to retail participants while preventing micro-contracts that amplify speculation. Source: SEBI Circular SEBI/HO/MRD2/DCAP/P/CIR/2021/616; NSE Derivatives Trading Circulars (semi-annual).
How It Works Mechanically
Lot size is fixed for all contract series (near month, mid month, far month) at the time of revision. It does not change during the contract's life — only at the semi-annual review. NSE announces revised lot sizes typically 2–3 weeks before they take effect. Open positions in the old contract (unexpired) continue with the old lot size until expiry. New contracts opened after the effective date carry the revised lot size.
How SEBI/NSE determine lot size: Target notional = lot size × underlying price. If a stock is at ₹4,000 and target is ₹5,00,000 notional, lot size = 125. If the stock rises to ₹5,000 by next review (notional ₹6,25,000 — within ₹5–10L range), lot size may stay 125. If stock rises to ₹8,000 (notional ₹10,00,000 — at ceiling), lot is revised down to ~62 or 65 to bring it back toward ₹5L. Conversely, if a stock falls from ₹2,000 (lot 250, notional ₹5,00,000) to ₹800 (notional ₹2,00,000 — below floor), lot is increased to ~625.
For Index contracts: Nifty 50 lot size was revised to 25 units (November 2024 per NSE circular); Nifty Bank was revised to 15 units (May 2023). Always verify current lot sizes from the NSE website as they change semi-annually.
For commodity futures (MCX/NCDEX): lot sizes are fixed in commodity units (e.g., MCX Gold Mini = 100 grams) and are reviewed less frequently.
Cost Components
- Margin: Buying/selling one lot of futures requires SPAN + exposure margin (typically 15–20% of notional contract value). For Nifty at ₹22,000, lot 25, notional ₹5.5L → margin ~₹70,000–₹1,05,000.
- STT on F&O: Options buy: nil. Options sell (exercise/expiry): 0.125% on intrinsic value. Futures sell: 0.0125% on notional value.
- Exchange charges: NSE equity derivatives ₹2/lakh turnover.
- GST: 18% on brokerage + exchange charges.
- Brokerage: ₹20/lot for discount brokers on options; ₹20/order for futures.
Risk / Protection Rules
- SEBI lot-size revision: Semi-annual revision ensures contracts remain economically meaningful — prevents micro-lot proliferation that would lower entry barriers excessively in high-risk instruments.
- Position limits: SEBI caps single-entity F&O position at the lower of 20% of market-wide position limit (MWPL) or 500 lots for index contracts, preventing corners and manipulation.
- MWPL monitoring: When total open interest in a stock's F&O crosses 95% of MWPL, fresh positions are banned. Lot size is a direct input: smaller lots → more contracts possible → MWPL reached faster.
- F&O carries leverage which amplifies BOTH gains and losses. A single Nifty lot move of 1% represents ₹5,500 gain or loss on ~₹85,000–₹1,00,000 margin — approximately 5–7% of margin in one day from a 1% index move.
Worked Example
Stock ABC is at ₹1,200. Lot size = 400 (notional = ₹4,80,000 — at review threshold). NSE revises lot to 500 (notional = ₹6,00,000) at the next semi-annual revision. A trader who previously bought 2 lots (800 shares exposure) of ABC Call at ₹30 premium paid ₹24,000 total premium. After revision, buying 2 lots costs ₹30 × 1,000 = ₹30,000 premium for the same ₹30 option — they now get 1,000 shares of exposure vs. 800 previously. Same percentage gain/loss but larger absolute P&L per unit premium increase.
Caveats / Common Mistakes
- Always verify current lot size from NSE/BSE website before placing orders — lot sizes change without prominent alerting in most trading apps.
- Lot size revisions cause premium changes on existing open positions at rollover — this confuses traders comparing month-to-month premium levels.
- F&O trading involves leverage. The SEBI study (July 2024) showed 89% of individual F&O traders incurred net losses over FY22–FY24. Lot size is a factor — larger lots at lower-priced stocks amplify P&L volatility.
See Also
Primary Source
MintByte (ARN-314872 / APMI APRN-01658) provides this glossary for educational purposes only. Nothing here constitutes investment advice, a recommendation to buy or sell any security, or a guarantee of returns. Equity and derivatives trading involves risk of loss. Consult a SEBI-registered adviser before making investment decisions.