Chapter 15: Investment through Secondary Market

Trading on modern Indian stock exchanges (NSE, BSE) operates via an automated, nationwide, screen-based trading system (SBTS) powered by an electronic Continuous Open Order Book.

In an open order book system:

• Buy orders (bids) and sell orders (offers/asks) are placed anonymously by investors across the country through licensed stock brokers.
• Orders are matched automatically by the exchange matching engine based on strict Price-Time Priority:
  • Price Priority: The highest buy order and the lowest sell order always take priority over all other orders.
  • Time Priority: When two orders are placed at the exact same price, the order entered earlier in time is matched and executed first.
• The order book displays the market depth (the top 5 or 20 bids and asks with corresponding quantities), providing transparent real-time visibility into market liquidity and supply-demand balance.

Investors can utilize several order types to control price execution and manage risk:

1. Market Order

• An order to buy or sell a security immediately at the best available prevailing market price.
• Execution: Guarantees execution speed, but does not guarantee the exact price. In fast-moving or thinly traded securities, market orders can suffer from slippage (executing at prices worse than anticipated).

2. Limit Order

• An order to buy a security at or below a specified price, or sell a security at or above a specified price.
• Execution: Guarantees that the investor will not pay more (or receive less) than the chosen limit price. However, execution is not guaranteed if the market price does not reach the limit level.

3. Stop-Loss Order (SL)

Designed to limit an investor's loss on an existing position by automatically triggering an exit when the market moves against them:

• Stop-Loss Limit (SL-L): Contains two prices—a Trigger Price and a Limit Price. When the market trades at or crosses the trigger price, the order becomes an active limit order at the limit price.
• Stop-Loss Market (SL-M): Contains only a Trigger Price. When the market reaches the trigger price, the order becomes an immediate market order and executes at the best available price.

When placing secondary market orders, traders can specify operational conditions to refine execution:

• Day Order: Remains active until executed or until the close of the trading day, after which any unfilled quantity is automatically canceled.
• Immediate or Cancel (IOC): Requires the order to be executed immediately upon reaching the market. Any unfilled portion that cannot be matched instantly is canceled on the spot without entering the order book.
• Disclosed Quantity (DQ): Allows an investor placing a large order to reveal only a fraction of the total quantity to the public market depth (minimum 10% of total quantity under exchange rules), concealing the true order size to minimize market impact.