NISM Series IV · Chapter 6: Trading Mechanism in Exchange Traded IRD

L1 · Foundation

Foundation — Who is who in the trading system, and how the exchange platform works

Why ETIRD sits inside the currency derivatives segment; the statutory definition of a stock exchange and its seven functions; trading members, authorised persons, clearing members and the NISM certification requirement; the client, UCC and PAN mapping; the nine features of the exchange trading system; the trader workstation; and the channels through which orders reach the exchange.

26 min read · Worth 10% of the paper · Written from pages 192–223 of the official NISM workbook · Updated 18 September 2026

Chapter 6 — Trading mechanism in Exchange Traded Interest Rate Derivatives

Weightage: 10%. This chapter is almost entirely institutional detail and procedure — which makes it very testable and very learnable. Numbers, thresholds, timelines and names carry most of the marks.

1. Where ETIRD actually sits

Stock exchanges provide multiple segments — Equity, Equity Derivatives, Currency Derivatives, Commodity Derivatives, Interest Rate Derivatives, Debt Securities. Generally the segments are specific to the underlying asset.

In plain words: there is no separate segment for interest rate derivatives. You trade them in the currency derivatives segment.

And as with all derivatives exchanges:

In plain words: the exchange runs trading. A separate company, the clearing corporation, clears and settles the trades.

The statutory definition. The Securities Contracts (Regulation) Act, 1956 defines a stock exchange as (a) any body of individuals, whether incorporated or not, constituted before corporatisation and demutualisation under sections 4A and 4B, or (b) a body corporate incorporated under the Companies Act, 1956, whether under a scheme of corporatisation and demutualisation or otherwise, for the purpose of assisting, regulating or coordinating the business of buying, selling or dealing in securities.

In plain words: you cannot trade on the exchange yourself. You must go through a registered broker.

2. The entities in the trading system

2.1 Stock Exchanges

Their important role is to establish a nation-wide trading facility and ensure equal access to investors across the nation through an appropriate communication network. They set out and implement rules and regulations covering member registration, securities listing, transaction monitoring, compliance by members with SEBI/RBI regulations, and investor protection.

The seven typical functions:

Provide trading platform
Dissemination of information
Investor education, awareness and protection.
Facilitate redressal mechanism
Surveillance and investigation
Listing of securities and monitoring compliance of listed companies.
Inspection and monitoring of member compliance.

In plain words: BSE, NSE and MSEI offer these contracts, each in its currency derivatives segment.

2.2 Clearing Corporations

The CC does clearing, settlement and risk management for trades executed on exchanges, and also provides a settlement guarantee for such trades. Its functions are covered in detail in Chapter 7.

2.3 Trading Member and Authorised Person

A trading member / stock broker is a member of the stock exchange, and "stock broker" means a person having trading rights in any recognised stock exchange, and includes a trading member. Eligibility is specified under the SEBI Stock Broker Regulations 2026 and the Securities Contracts Regulation Rules 1957.

A trading member is allowed to execute trades on his OWN account as well as on account of his CLIENTS.
A trading member can be an individual (sole proprietor), a partnership firm, an LLP, a corporate or a bank who is a member of a stock exchange. (Banks are permitted to become members of the currency derivatives segment subject to fulfilling minimum prudential requirements.).

Admission as a trading member is based on criteria including age, capital adequacy, financial track record, education, experience and fulfilment of the "fit & proper person" criteria laid down in the SEBI (Intermediaries) Regulations, 2008. ⚠️ Exchanges may stipulate ADDITIONAL requirements over and above the SEBI prescribed rules.

2.4 The certification requirement — read this carefully

In plain words: a Series I certificate lets a dealer into the segment. It does not let the dealer place orders in interest rate derivatives.

Access to the segment and eligibility to trade the product are two different things. That distinction is a very likely exam question — and it is the reason you are reading this workbook.

2.5 Membership categories

Membership of the currency derivatives segment can be taken individually or in combination:

Trading member only
Trading cum self-clearing member
Trading cum clearing member

2.6 Clearing Members

Clearing members have clearing and settlement rights in a recognised clearing corporation and help in clearing the trades of their clients. Three kinds:

Professional Clearing Members (PCM)
Trading Cum Clearing Member (TCM).
Self Clearing Member (SCM)

2.7 Investor / Client

Investors trade in ETIRD through a trading member of the currency derivatives segment, who accepts the order on behalf of the client and sends it to the exchange. Investors include retail individuals, HNIs, domestic institutional investors like banks and mutual funds, foreign portfolio investors and corporate entities.

To participate, an investor must open a trading account with a trading member of the currency derivatives segment and complete account opening, KYC etc.

⚠️ Then the UCC rules apply, and these are heavily tested:

Once KYC is complete, each client is assigned a UNIQUE CLIENT CODE (UCC) by the broker, which acts as an identity for the client with respect to the broker.
SEBI has made it MANDATORY for all brokers to use unique client codes for all clients while entering orders on their behalf.
SEBI also mandates that the UCC be MAPPED WITH THE PAN NUMBER of the client.
The broker must provide the exchange with the UCC and PAN details BEFORE entering any order/trade on behalf of the client.
Exchanges provide an upload facility through which UCC and other client details are uploaded on a regular basis.
⚠️ If the broker fails to register the unique client code with the exchange, he is liable to be PENALISED.

In plain words: each client gets a unique client code linked to PAN. The broker must register it with the exchange before placing any order, or face a penalty.

3. The exchange trading system

All derivatives exchanges in India provide a fully automated screen-based trading platform for ETIRD as part of the currency derivatives segment. These systems support an ORDER DRIVEN market and simultaneously provide complete transparency of trading operations.

The nine important features:

Screen based trading system
Fully automated — NO manual intervention.
Transparent — quantity and price information related to order and trade is disseminated on a real time basis.
⚠️ Anonymous order matching — the identity of buyer and seller is NOT revealed to the market. Only price and quantity information is available. It is an order driven platform where order matching is done strictly on PRICE-TIME PRIORITY basis.
Higher speed of execution — handling of multiple orders and trade execution.
Connected to multiple interfaces — the clearing corporation system, the exchange's surveillance system, and data vendor systems for dissemination.
Risk management facility — mainly to avoid order entry related errors.
Nationwide reach — members can access from any part of the country.
Multiple connection modes — lease line, Internet, co-location.

In plain words: trading is fully automatic and screen-based, with live prices for all. Buyers and sellers stay anonymous. Members can connect from anywhere in India.

(Co-location or proximity hosting is a facility offered by stock exchanges to brokers and data vendors whereby their trading or data-vending systems are located within or close to the exchange premises and connect to the trading platform through a direct and private network.)

3.1 Trader Workstation (TWS)

TWS provides two kinds of information:

The trading member's own transaction information	Market information
Order entered	Order book
Order modified	Securities / contract price information
Outstanding order	Securities / contract trade information
Order log	Additional information
Trade details

⚠️ A detail specific to this product: since the final settlement of cash settled GOI bond futures and options is the weighted average price of the underlying bond over the last two hours of trading on NDS-OM, the exchange TWS also disseminates the trade prices of underlying GOI securities traded on NDS-OM on a REAL-TIME basis.

Customised workstations. Exchanges allow members to develop their own customised trading workstation and connect to the exchange trading system, through: CTCL (Computer to Computer Link), IBT (Internet Based Trading), DMA (Direct Market Access), STWT (Securities Trading using Wireless Technology), ALGO (Automated / Algorithmic Trading) and SOR (Smart Order Router).

4. Placing an order

The broker accepts orders from the client and sends them to the exchange AFTER performing risk management checks. Clients may place orders through internet, phone, DMA (for institutional clients), STWT, ALGO, SOR and similar channels.

4.1 Evidence of client orders — a compliance requirement

Acceptable forms of evidence:

(a) Physical record written and signed by client · (b) Telephone recording · (c) Email from authorised email id · (d) Log for internet transactions · (e) Record of SMS messages · (f) Any other legally verifiable record.

When a dispute arises, the broker shall produce these records for the disputed trades.
⚠️ Wherever order instructions are received by TELEPHONE, the stock broker shall MANDATORILY use a telephone recording system to record instructions and maintain the recordings as part of its records (SEBI circular dated 22 March 2018).
Records must be kept for the minimum period for which arbitration accepts investors' complaints — CURRENTLY THREE YEARS.
⚠️ Where a dispute has been raised, records shall be kept TILL FINAL RESOLUTION of the dispute. If SEBI desires specific records preserved, they shall be kept till further intimation by SEBI.

In plain words: a broker trades for a client only with proof of the client's order. Phone orders must be recorded. Keep the records for three years, or until any dispute is fully resolved.

4.2 Internet trading

Internet trading takes place through order routing systems which route client orders to exchange trading systems for execution, so a client anywhere in the country can trade. SEBI-registered brokers can introduce internet based trading after obtaining permission from the respective stock exchanges, and SEBI stipulates minimum conditions to be fulfilled.

4.3 Direct Market Access (DMA)

Advantages of DMA:

Direct control of clients over orders.
Faster execution of client orders.
Reduced risk of errors associated with manual order entry.
Greater transparency
Increased liquidity
Lower impact costs for large orders.
Better audit trails
Better use of hedging and arbitrage opportunities through decision support tools / algorithms.

The rules:

SEBI introduced DMA in 2008 and permitted INSTITUTIONAL investors to use it.
The DMA facility shall be used by the client or an INVESTMENT MANAGER of the client. A SEBI registered entity is permitted to act as investment manager on behalf of institutional clients; if DMA is used through an investment manager, the investment manager must execute the necessary documents on behalf of the client(s).
The exchange can specify the categories of investors to whom DMA can be extended.
Brokers can introduce DMA after obtaining permission from the respective stock exchanges.
Brokers must specifically authorise clients or investment managers, after fulfilling KYC requirements, documentation and necessary due diligence, with records properly maintained.
⚠️ The broker shall be FULLY RESPONSIBLE AND LIABLE for ALL orders emanating through their DMA systems, and it is the broker's responsibility to ensure only eligible clients use it.

In plain words: DMA lets approved clients send orders straight to the exchange through the broker's systems. SEBI allowed it for institutions in 2008. The broker must get the exchange's permission and is fully liable for every DMA order.

4.4 Algorithmic Trading and High Frequency Trading

SEBI's requirements:

⚠️ All algorithmic orders must be routed through broker servers LOCATED IN INDIA.
The exchange must have appropriate risk control mechanisms to address risk from algorithmic orders and trades.
⚠️ Minimum order-level risk controls shall include PRICE CHECK and QUANTITY LIMIT CHECK.
The broker shall provide the algorithmic trading facility only upon PRIOR PERMISSION of the stock exchange, and must satisfy the exchange regarding implementation of minimum risk controls.
⚠️ Brokers providing algorithmic trading shall subject their algorithmic trading system to a SYSTEM AUDIT EVERY SIX MONTHS.

In plain words: algo orders must go through broker servers in India, with at least price and quantity checks. The broker needs the exchange's prior permission. Its algo system must be audited every six months.

SEBI's circular dated February 04, 2025 provided guidelines for retail investor participation in algorithmic trading through brokers, covering use of Application Programming Interface (API) for algo trading by retail investors, roles and responsibilities of stock brokers and stock exchanges, empanelment and registration of Algo Providers, and categorisation of Algos.

5. Order routing and confirmation

Once the order is entered and confirmed by the client/dealer at his trading terminal and verified by the broker software, the order is routed to the exchange for execution.

⚠️ The exchange system allots a UNIQUE ORDER NUMBER for all orders received, given as order confirmation ALONG WITH THE TIME STAMP to the broker.
A market order gets executed immediately, subject to availability of a counter order. A limit order is matched against appropriate counter orders.
Once the order is matched, a trade is said to be executed, and the trade confirmation message along with time stamp is automatically available on the broker's trading terminal.
⚠️ All orders can be modified or cancelled during trading hours PROVIDED THEY ARE NOT FULLY EXECUTED. For partially executed orders, ONLY the open or unexecuted part can be cancelled or modified.

In plain words: each order gets a number and a time stamp. Market orders execute at once if there is a counter order. You can change or cancel an order until it fully executes, but only the unfilled part.

Think of it like this

Two different companies run the match — the umpire and the scorer

At a cricket match, the umpire decides what happens on the field, ball by ball. A completely separate scorer records it all, reconciles the books and produces the official result.

Exchange trading works the same way, and the workbook is precise about it: "trading and settlement are conducted by two distinct legal entities: trading by Exchange and settlement (along with the associated process of Clearing) by Clearing Corporation."

The exchange brings buyer and seller together and matches the order. The clearing corporation settles it, manages the risk, and guarantees it. Two entities, two jobs — which is why a trading member and a clearing member are separate memberships, and why a plain "trading member" must route his clearing through a Trading-cum-Clearing Member or a Professional Clearing Member.

And one geographic oddity worth remembering: interest rate derivatives are not a segment of their own — they sit inside the CURRENCY derivatives segment.

Best buy and best sell — reading the price board from the other side

Walk into a vegetable market wanting to sell tomatoes. Five buyers are calling out Rs 40, Rs 38, Rs 35, Rs 32, Rs 30. Which is the "best" price? Rs 40, the highest — because you are the seller.

Now walk in wanting to buy. Five sellers ask Rs 45, Rs 47, Rs 50, Rs 52, Rs 55. The "best" is Rs 45, the lowest.

That is exactly the workbook's reasoning: "the system views all buy orders available from the point of view of a SELLER and all sell orders from the point of view of the BUYER." Hence the best buy order is the one with the HIGHEST price and the best sell order is the one with the LOWEST price — which is why the order book lists buy prices in descending order and sell prices in ascending order, with the best of each sitting at the top.

Both sides converge in the middle, and the gap between them is the spread.

Passive and active orders — the shopkeeper and the customer

A shopkeeper puts a price tag on a shirt: Rs 900. He then waits. That tag is a passive order — sitting in the book, unmatched, offering terms.

A customer walks in and buys it. That is the active order — it came in to match what was already there.

At what price does the sale happen? Rs 900 — the shopkeeper's price. Even if the customer was privately willing to pay Rs 950.

That is the rule the workbook states: "Orders are always matched at the PASSIVE order price." So when a client places a limit buy at Rs 807.65 and the best resting sell is Rs 807.60, the trade happens at Rs 807.60 and the client gets a better fill than his own limit. His remaining quantity then becomes passive itself, sitting at the top of the buy side.

One more thing follows: quantity is not a factor for matching. The shopkeeper's tag does not go to whoever wants the most shirts — it goes to whoever got there first at the best price.

A stop loss is an alarm, not a sale

You set an alarm on your phone for 6 a.m. The alarm does not get you out of bed — it only wakes you up, and then you still have to walk to the bathroom, which takes time and may not happen instantly.

A stop loss order works the same way. You enter two prices — a trigger price and a limit (or market) price. Nothing at all sits in the market until the trigger is hit. "Until then the order does not enter the market."

Bought at Rs 100 and willing to lose 25 paise? Set the trigger at 99.80 and the limit at 99.75. When the price touches 99.80, the sell order at 99.75 is released into the market.

And here is the alarm's limitation, which the workbook states plainly: "once the order is triggered, it will match ONLY if the counter order is available in the order book." A stop loss limit at 99.75 will only fill "if a corresponding buy order exists for Rs 99.75 or better." In a fast-falling market, the alarm rings and nobody is there to buy. That is exactly why the alternative exists — stop loss with a market order, which "once triggered will match with the best counter order available."

Disclosed quantity — the shopkeeper who shows two sacks at a time

A wholesaler has 1,000 sacks of rice to sell. If he stacks all 1,000 in front of the shop, every buyer sees the glut and offers him less. So he keeps 200 sacks visible, and as each lot sells, he quietly brings out the next 200.

That is a Disclosed Quantity (DQ) order: an order of 1,000 lots with a DQ of 200 shows only 200 lots to the market at a time, and after each is traded another 200 is automatically released.

Contrast it with the two neighbouring conditions:

Minimum Fill (MF) — "I will not sell fewer than 200 sacks in any single deal." An order of 1,000 with MF 200 means at most 5 trades of 200, or a single trade of 1,000
All or None (AON) — "All 1,000 or nothing." If the full order is not matched it stays in the books till matched or cancelled

⚠️ Currently AON and MF orders are NOT available on the system as per SEBI directives — as are GTC and GTD. Know them, but know that they are switched off.

Key terms in this chapter

Active and passive orders: A passive order lies unmatched in the book; an active order arrives to match it. Every trade takes place at the passive order's price, which is why an aggressive limit order can be filled better than its own limit.
Algorithmic trading: Any order generated using automated execution logic, pushed into the exchange system without manual entry. It needs prior exchange permission, servers located in India, minimum price and quantity checks, and a system audit every six months.
Authorised person: Someone appointed by a stock broker who provides access to the exchange trading platform as an AGENT of the broker. An authorised person is not himself a member of the exchange; the sub-broker category has been discontinued.
Buy spread order (BSP): A spread order meaning sell the near month first leg and buy the far month second leg. A sell spread order is the mirror: buy the near month and sell the far month.
Co-location: A facility letting brokers and data vendors place their systems within or close to the exchange premises and connect through a direct private network — one of the permitted connection modes alongside lease line and internet.
Contract note: The official communication from broker to client confirming executed trades. A single order can produce multiple trade numbers, all of which reach the client through this document.
CSCRF: SEBI's Cybersecurity and Cyber Resilience Framework of August 2024, effective in phases from 1 January 2025, built on five goals — Anticipate, Withstand, Contain, Recover and Evolve — and requiring every regulated entity to have a Security Operation Centre.
Currency Derivatives Segment: The segment of a stock exchange within which exchange traded interest rate derivatives are traded. ETIRD has no segment of its own, which is why membership and dealer certification are framed around currency derivatives.
Direct Market Access (DMA): A facility allowing institutional clients direct access to the exchange trading system through the broker's infrastructure without manual intervention. The broker remains fully responsible and liable for every order it generates.
Disclosed Quantity (DQ): An order condition revealing only part of the quantity to the market at a time, with the next tranche released automatically as each trades — used to avoid signalling the full size of a large order.
Error account: A broker account into which mistaken trades are shifted. This is not treated as client code modification provided the trades are liquidated in the market rather than moved to another client code.
Fit and proper person: One of the admission criteria for a trading member, laid down in the SEBI (Intermediaries) Regulations, 2008, alongside age, capital adequacy, financial track record, education and experience. Exchanges may add requirements of their own.
High Frequency Trading (HFT): A latency-sensitive form of algorithmic trading marked by high daily portfolio turnover and a high order-to-trade ratio.
Investor Risk Reduction Access (IRRA): A joint exchange platform enabling investors to square off open positions or cancel pending orders when their trading member suffers a service disruption. It never permits any action that increases the investor's risk.
IOC order: Immediate or Cancel — executes as soon as it reaches the market, with any unmatched portion cancelled at once. Partial matching is possible.
iSPOT and LAMA: iSPOT is SEBI's web portal for reporting technical glitches and root cause analyses; LAMA is the API-based logging and monitoring mechanism through which exchanges watch key parameters of specified brokers' trading systems.
Kill switch: A facility letting a member cancel every outstanding order with a single command — the emergency brake of the trading system.
Legal risk: The possibility that a contract cannot be enforced against the other party — because the contract may be illegal, or because the counterparty entered it without proper authority.
Market depth: The quantity of lots available at each price point in the order book. It tells a trader how far a large order would move the price before being filled.
Market order with protection: A combination of market and limit order that lets a market order execute only up to a level the trader specifies, guarding against the order walking far up or down the book.
Market SOC (M-SOC): A shared Security Operation Centre that NSE and BSE are mandated to set up, so smaller regulated entities can meet CSCRF monitoring obligations without the expertise and cost of running their own.
Maximum brokerage: For futures, 2.5% of contract value exclusive of statutory levies; for options, 2.5% of the premium or Rs 100 per lot, whichever is higher. No minimum brokerage is prescribed.
Minimum Fill and All or None: MF sets the smallest quantity any single trade may fill; AON requires the entire order to be matched, possibly across several trades, and otherwise leaves it resting. Both are currently unavailable per SEBI directives.
Operational risk: Loss from inadequate or failed internal processes, manual and system errors or external events — for a broker, things like trading errors, non-delivery of scrips and denial of matched orders by clients.
Order book: The live electronic list of unmatched buy and sell orders organised by price level, showing quantity and number of orders at each of five price points. It is anonymous, dynamic and the market's main measure of depth.
Order driven market: A market where prices emerge from the buy and sell orders participants place, matched anonymously on strict price-time priority, rather than from quotes posted by designated market makers.
Price band (circuit filter): The daily range beyond which orders are not accepted — 3% for GOI bond futures (up to 4% after two relaxations), 1% for 91-day T-Bill futures, 5% of the base rate for MIBOR futures, and 5% for corporate bond index futures.
Price-time priority: The matching rule — best price first, and among orders at the same price, the earliest first. Quantity plays no part in deciding which order matches.
Pro and Cli: Order identifiers marking whether a trading member is dealing on his own account or on behalf of a client. Proprietary trades can never later be modified into client trades, or the reverse.
Reference price (spread trades): The last traded price of the first leg contract. The first leg trades at that price and the second leg at that price plus the spread difference entered on the order.
SEBI turnover fee: A fee payable by brokers and clearing members on securities transactions including off-market ones — currently Rs 5 per crore of turnover for interest rate derivatives, with clearing members also paying Rs 50,000 a year.
Self-trade check: A pre-trade control cancelling an order where the same PAN or CP code would appear on both the active and passive side, preventing a participant from trading with himself.
Software escrow arrangement: A safeguard brokers are advised to explore with software vendors, so that a vendor's failure to supply or support its software does not halt trading. Large brokers are also advised to use more than one vendor.
Spread order book: A separate book for calendar spread combinations, where the quoted price is the difference between the far month and near month contract — and can therefore be positive, negative or zero.
Stamp duty on ETIRD: Levied at 0.0001% on the buyer, collected at one place by one agency and shared with states by the buyer's state of domicile. Futures are valued at traded price and options at premium; STT does not currently apply to ETIRD.
Stop loss order: An order carrying a trigger price and a limit or market price, which stays out of the market until the trigger is reached or crossed. Once triggered, a limit version fills only if a counter order exists at that price or better.
Systemic risk: Either a domino effect where disruption at one firm or settlement system topples others, or a crisis of confidence among investors creating illiquid market conditions.
Trade annulment: Cancellation of an executed trade on request, normally within 30 minutes and never beyond 60. The application fee is 5% of trade value, between Rs 1 lakh and Rs 10 lakh, credited to the Investor Protection Fund.
Trader Workstation (TWS): The terminal from which a member accesses the trading system, reached through a unique Trading Member ID and User ID. For this product it also disseminates real-time NDS-OM prices of the underlying GOI securities.
Trading cum clearing member: A membership combination allowing a member both to trade and to clear. A plain trading member must route clearing and settlement through a trading-cum-clearing member or a professional clearing member.
Trading member (stock broker): A person having trading rights in a recognised stock exchange, entitled to execute trades on his own account and on behalf of clients. Investors in India cannot access the exchange platform directly and must trade through one.
Unique Client Code (UCC): The identity assigned to each client by the broker, mandatorily mapped to the client's PAN and supplied to the exchange before any order is entered on the client's behalf. Failure to register it makes the broker liable to penalty.

Check you have understood it

The L1 test for this chapter has 9 questions. Score 60% to unlock L2 Application (worked numericals and scenarios) and then L3 Exam-Ready (NISM-style traps, timed, with this paper's real marking). Tests, the higher levels and full mock exams need a free account so we can track your progress.

Create a free account

Original explanatory writing based on the official NISM workbook for Series IV, which is published and copyrighted by NISM. Check figures against the current edition at nism.ac.in.

Something look wrong? Report it