NISM-Series-XXI-A: Portfolio Management Services (PMS) Distributors · Investing in Stocks (NISM XXI-A)

Secondary Market and Trading Mechanism for NISM XXI-A

Updated 11 October 2026 · Fact-checked

The secondary market is where investors buy and sell already issued securities on stock exchanges. Orders match on the exchange's electronic system, the clearing corporation guarantees and nets the trades, and settlement moves money and shares. Shares are held in a demat account. Indices like Sensex and Nifty track market movement.

Understand Secondary Market and Trading Mechanism

The primary market is where a company issues new securities and receives the money. The secondary market is where investors trade those securities among themselves. The company gets no new money from these trades. Its main job is to give liquidity (you can sell when you want) and price discovery (the price reflects what buyers and sellers are willing to pay).

In India, trading happens on stock exchanges such as BSE and NSE. Trading is screen-based and order-driven. Brokers who are trading members place buy and sell orders from their clients. The exchange system matches orders by price-time priority: the best price gets matched first, and at the same price the earlier order goes first.

After a trade, the clearing corporation (for example NSE Clearing or Indian Clearing Corporation) works out what each member must pay or deliver. It acts as the counterparty to both sides, which removes the risk that the other party defaults. Then settlement happens: money moves between bank accounts and shares move between demat accounts. The standard cycle for equity in India is T+1, meaning settlement on the next working day after the trade day (T).

Shares are held in electronic form in a demat account with a depository participant (DP). The two depositories are NSDL and CDSL. A trading account lets you place orders. A demat account holds the shares. A bank account handles the money.

A market index measures the movement of a group of stocks. Sensex is the BSE index of 30 stocks. Nifty 50 is the NSE index of 50 stocks. Both are weighted by free-float market capitalisation, which counts only shares available for public trading. Exams also test order types: market, limit, stop-loss, and validity such as day orders.

Key formulas to remember

Settlement date (T+1): Settlement day = Trade day (T) + 1 working day; Weekends and exchange holidays are not counted. A Friday trade settles on Monday if Monday is a working day.
Free-float market capitalisation: Free-float market cap = Share price × Number of free-float shares; Free-float shares exclude promoter and other locked-in or strategic holdings.
Free-float index value: Index value = (Current total free-float market cap ÷ Base market cap) × Base index value; Sensex and Nifty use this idea. A divisor or base value adjusts for corporate actions so the index is not distorted.
Trade value: Trade value = Price × Quantity; Used to find the money paid or received at settlement, before charges and taxes.
Order matching priority: Price first, then time; Highest bid and lowest offer get priority. Equal prices are matched in order of arrival.

How to solve Secondary Market and Trading Mechanism questions

Most questions here test definitions, who does what, and order or settlement rules. Use this method.

1Identify what is asked: a definition, a role, a timeline, an index method, or an order type.
2Place the event in the trade life cycle: order, execution, clearing, settlement, demat credit.
3Match the role to the right entity: broker for orders, exchange for matching, clearing corporation for guarantee and netting, depository for electronic holding.
4For settlement dates, count working days only from the trade day. Skip weekends and holidays.
5For index questions, check whether the method is free-float market cap weighted, and whether the question is about a calculation or a concept.
6For order types, check the price condition (limit or market) and the validity (day or other), then pick the order that fits the investor's intent.
7Eliminate options that give the wrong entity, a wrong cycle or a mixed-up index, then pick the one that fits every condition.

Quickest way: Role and timeline shortcut

When to use it: Use this for one-line MCQs on who does what and when settlement happens.

Think in order: Broker places, Exchange matches, Clearing corporation guarantees, Depository holds.
Equity cash market settles T+1 on working days.
Sensex means BSE 30 stocks. Nifty 50 means NSE 50 stocks. Both use free-float.
Limit order controls price. Market order controls speed. Stop-loss triggers at a set price.
If an option names the wrong entity for the job, drop it at once.

Common mistakes in Secondary Market and Trading Mechanism

Thinking the company receives money when shares trade in the secondary market.
Students mix up primary and secondary markets.
Fix: Remember that secondary trades are between investors. Only primary issues raise fresh money for the company.
Counting weekends and holidays when finding the settlement date.
Students count calendar days instead of working days.
Fix: Count only working days. A Friday trade under T+1 settles on the next working day, normally Monday.
Confusing the roles of the clearing corporation and the depository.
Both work after the trade and both sound like back-office bodies.
Fix: The clearing corporation guarantees and nets trades. The depository holds securities in electronic form. NSDL and CDSL are depositories.
Saying Sensex and Nifty use full market capitalisation.
Older textbooks described full market cap weighting.
Fix: Both use free-float market capitalisation, which excludes shares not available for public trading.
Assuming a limit order is always executed.
Students focus on the price they want and ignore the market price.
Fix: A limit order executes only at the limit price or better. If the market never reaches it, the order stays unexecuted.
Mixing up Sensex and Nifty details, such as the number of stocks or exchange.
Both are headline indices and the facts look alike.
Fix: Sensex is BSE with 30 stocks. Nifty 50 is NSE with 50 stocks.

Worked examples

Example 1

An investor buys shares on Thursday. There are no holidays that week. Under the T+1 cycle, on which day does the trade settle?

Show the solution

The trade day is T = Thursday.
T+1 means one working day after the trade day.
The next working day after Thursday is Friday.
No holiday falls on Friday, so no extra day is added.

Answer: The trade settles on Friday.

Example 2

A stock trades at ₹500. A company has 10,00,000 shares in issue, of which promoters hold 6,00,000 shares. What is its free-float market capitalisation?

Show the solution

Free-float shares = Total shares − Promoter shares = 10,00,000 − 6,00,000 = 4,00,000.
Free-float market cap = Price × Free-float shares.
= ₹500 × 4,00,000 = ₹20,00,00,000.

Answer: The free-float market capitalisation is ₹20,00,00,000 (₹20 crore).

Exam tips

Learn the trade life cycle in order. Many questions ask which step comes next or which body performs it.
Watch for options that use the right words for the wrong entity, such as a depository doing the guarantee work.
For settlement date questions, read any holiday information given before you count.
For index questions, remember free-float method and the stock counts and exchange for each index.
Know the intent behind each order type. A question may describe the investor's goal and ask for the matching order.

Practice questions from Investing in Stocks (NISM XXI-A)

Secondary Market and Trading Mechanism in other exams

The same ground in other exams, if you are preparing for more than one or want another angle on it.

Secondary Market and Trading Mechanism: frequently asked questions

How does stock exchange trading work in India?

Investors place orders through a broker. The exchange's electronic system matches buy and sell orders by price and then time. The clearing corporation then handles settlement of money and shares.

What is the T+1 settlement cycle?

T+1 means a trade settles one working day after the trade day. Money and shares are exchanged on that day. Weekends and exchange holidays are not counted.

What is the difference between Sensex and Nifty?

Sensex is the BSE index of 30 stocks. Nifty 50 is the NSE index of 50 stocks. Both are weighted by free-float market capitalisation.

Why do I need a demat account to trade shares?

Shares are held in electronic form, and the demat account with a depository participant holds them. You also need a trading account to place orders and a bank account for money.