Dean's Office Official Model Question Paper

Market Microstructure

Market microstructure is the branch of financial economics that investigates the explicit trading mechanisms, order execution protocols, bid-ask spread determination, transaction costs, and price discovery processes in financial exchanges.

Order-Driven vs. Quote-Driven Market

• Order-Driven Market (e.g., NEPSE): Buyers and sellers submit limit and market orders directly into a central order book; matching occurs automatically according to price-time priority without market makers.
• Quote-Driven Market (e.g., NASDAQ): Designated market makers/dealers continually quote two-way bid and ask prices, standing ready to buy or sell from their own inventory.

Market Order vs. Limit Order

• Market Order: An instruction to execute immediately at the best currently available market price, prioritizing execution speed over price certainty.
• Limit Order: An instruction to execute only at a specified limit price or better, prioritizing price certainty over execution certainty.

Bid-Ask Spread

The bid-ask spread is the difference between the lowest price a seller is willing to accept (Ask) and the highest price a buyer is willing to pay (Bid):

$$\text{Spread} = \text{Ask Price} - \text{Bid Price}$$

It represents the primary transaction cost of immediacy paid by liquidity demanders.

Role of CDSC in Nepal

CDSC acts as the national central depository and clearing house, maintaining electronic dematerialized (demat) shares in Central Depository Systems, facilitating electronic trade settlement on a $T+2$ rolling basis, and guaranteeing electronic title transfer.

Trade Life Cycle on the Nepal Stock Exchange (NEPSE)

The trade life cycle traces an equity transaction from order placement to final share delivery:

Order Entry (TMS) -> Pre-Trade Validation -> Order Matching (NEPSE) -> Clearing (CDSC) -> Settlement (T+2)

1. Pre-Trade Phase (Client to Broker TMS)

• Investor Onboarding: The investor holds an active Trading Account with a licensed brokerage firm, a Demat Account with a Depository Participant (DP), and a MeroShare account linked to a bank via C-ASBA.
• Pre-Trade Risk Management (RMS): When entering a Buy order on the Trade Management System (TMS), the system automatically validates available collateral (25% cash deposit or bank guarantee). For Sell orders, it electronically checks with CDSC to verify free demat share availability.

2. Trade Execution Phase (NEPSE Matching Engine)

• Order Routing: TMS routes valid orders to the NEPSE central matching engine.
• Continuous Auction Matching: Orders are matched based on Price-Time Priority (highest buy price and lowest sell price get execution priority; orders at the same price are executed chronologically).
• Trade Confirmation: Once matched, execution notices are instantly dispatched to buyer, seller, and brokers.

3. Post-Trade Clearing and Settlement Phase (CDSC)

• Clearing (Netting): CDSC aggregates all inter-broker transactions at the end of the trading day ($T$), calculating net share obligations and net cash pay-in/pay-out figures.
• Electronic Settlement ($T+2$ Rolling Cycle):
  • By $T+2$ (two business days following trade date), the selling investor authorizes electronic Electronic Delivery Instruction Slip (EDIS) on MeroShare, transferring demat shares to the broker pool.
  • The buyer pays the net cash consideration via connectIPS.
  • CDSC transfers shares into the buyer’s demat account and credits the seller’s bank account.

Market Liquidity and Its Three Core Dimensions

Market liquidity is the ability of market participants to execute large transactions rapidly with minimal transaction costs and negligible price impact.

+----------------------------------------------------------------------+
|                     THE THREE DIMENSIONS OF LIQUIDITY                |
+-------------------+--------------------------------------------------+
| 1. Tightness      | Narrowness of the bid-ask spread                 |
| 2. Depth          | Order book volume existing at best quotes        |
| 3. Resiliency     | Speed with which prices recover after big trades |
+-------------------+--------------------------------------------------+

1. Core Dimensions of Liquidity

1. Tightness (Spread):
   • Measures how close the best bid and best ask prices are. A tight spread (e.g., Rs. 0.50 difference) implies low transaction cost for immediate execution.
2. Depth (Order Book Volume):
   • Measures the aggregate volume of limit orders available at and immediately behind the best bid and ask quotes. High depth allows institutions to execute large orders without moving market prices significantly.
3. Resiliency:
   • The speed with which price deviations caused by temporary liquidity shocks (e.g., a massive institutional market sell order) are corrected as new limit orders enter the book.

2. Influence of Market Makers and Algorithmic Trading

• Market Makers: Contractually obligated to post continuous two-way bid/ask quotes, directly narrowing spreads (tightness) and providing immediate buffer volume (depth).
• Algorithmic & High-Frequency Trading (HFT): Algorithms monitor tick data across multiple assets, posting rapid limit orders and providing tight liquidity during normal conditions, though they may abruptly withdraw liquidity during extreme market crashes (flash crashes).

Financial Intermediaries and Bid-Ask Spread Economics

1. Institutional Roles in Securities Trading

• Brokers (Pure Agents): Intermediaries who match buyers and sellers for a commission without committing personal capital or holding inventory risk.
• Dealers (Principals): Intermediaries who trade securities for their own accounts, holding inventory and profiting from the spread between buying at the bid and selling at the ask.
• Market Makers: Formally designated dealers obligated by exchange rules to maintain continuous two-sided liquidity in specified stocks.

2. Determinants of the Dealer Bid-Ask Spread (Microstructure Models)

According to Stoll (1989) and Glosten-Milgrom (1985), the bid-ask spread compensates dealers for three distinct operational costs:

$$\text{Bid-Ask Spread} = \text{Order Processing Costs} + \text{Inventory Holding Costs} + \text{Adverse Selection Costs}$$

1. Order Processing Costs: Direct administrative expenses of executing trades, exchange fees, clearing charges, and communication technology.
2. Inventory Holding Costs (Ho & Stoll):
   • Holding a block of stock exposes the dealer to price volatility risk and ties up financing capital. If a dealer accumulates excess inventory, they lower both bid and ask quotes to discourage sellers and entice buyers.
3. Adverse Selection Costs (Informed Trader Risk):
   • Dealers face two types of counterparties: uninformed liquidity traders and informed traders possessing private superior information. When trading with an informed trader, the dealer always loses. To compensate for these expected losses, the dealer widens the spread charged to all traders.

Margin Trading, Short Selling, and Regulatory Oversight in Nepal

1. Margin Trading Mechanics

Margin trading enables investors to purchase securities using borrowed funds provided by a licensed brokerage firm:

• Initial Margin: The minimum percentage of equity capital the investor must deposit upfront (e.g., 50% initial margin on a Rs. 1,000,000 purchase requires Rs. 500,000 investor cash and Rs. 500,000 broker loan).
• Maintenance Margin: The minimum equity threshold (typically 30–40%) that must be maintained as market prices fluctuate:
  $$\text{Actual Margin} = \frac{\text{Market Value of Securities} - \text{Broker Loan}}{\text{Market Value of Securities}}$$
• Margin Call: If the stock price falls and actual margin drops below maintenance margin, the broker issues an immediate margin call requiring cash top-up within 24–48 hours. If unmet, the broker liquidates the collateral stock.

2. Short Selling Mechanics

• An investor borrows shares from a broker, sells them in the market expecting a price drop, and buys them back later at a lower price to return them to the lender, pocketing the price difference.

3. Why SEBON Strictly Monitors Short Selling in Nepal

• Preventing Market Manipulation: Emerging markets like NEPSE feature low free-float market capitalization and concentrated ownership. Unregulated short selling could allow syndicates to orchestrate bear raids, spreading rumors and shorting stocks to trigger cascading panics.
• Absence of Securities Lending and Borrowing (SLB) Infrastructure: Nepal lacks a formal institutional SLB clearing mechanism; naked short selling could cause massive settlement delivery defaults.
• Retail Investor Protection: Most Nepalese investors are retail participants who lack sophisticated risk-management tools to withstand leveraged short squeezes.

Comprehensive Solution: Limit Order Book Dynamics

(a) Inside Market, Spread, and Midpoint (5 Marks)

• Best Bid (Highest price a buyer offers): $\mathbf{\text{Rs. } 350.00}$ (Trader 1, 2,000 shares)
• Best Ask (Lowest price a seller accepts): $\mathbf{\text{Rs. } 352.00}$ (Trader 5, 1,500 shares)

1. Quoted Bid-Ask Spread ($S$):
   $$S = \text{Best Ask} - \text{Best Bid} = 352.00 - 350.00 = \mathbf{Rs.\ 2.00}$$
2. Midpoint Quote ($M$):
   $$M = \frac{\text{Best Bid} + \text{Best Ask}}{2} = \frac{350.00 + 352.00}{2} = \mathbf{Rs.\ 351.00}$$
3. Percentage Spread:
   $$\%\text{Spread} = \left(\frac{S}{M}\right) \times 100 = \left(\frac{2.00}{351.00}\right) \times 100 = \mathbf{0.57\%}$$

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(b) Execution of Market Buy Order for 3,500 Shares (5 Marks)

A Market Buy order executes by walking up the sell side of the order book (consuming ask liquidity):

• Remaining lot of Trader 6 in order book: $2,500 - 2,000 = 500\text{ shares @ Rs. } 353.00$.
• Volume-Weighted Average Price (VWAP):
  $$\text{VWAP} = \frac{\text{Total Cash Cost}}{\text{Total Shares Executed}} = \frac{\text{Rs. } 1,234,000}{3,500} = \mathbf{Rs.\ 352.5714\ per share}$$

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(c) Effective Spread and Price Impact (5 Marks)

• Pre-Trade Midpoint ($M$) = $\text{Rs. } 351.00$
• Average Execution Price ($P_{exec}$) = $\text{Rs. } 352.5714$

1. Effective Spread:
   $$\text{Effective Spread} = 2 \times |P_{exec} - M| = 2 \times |352.5714 - 351.00| = 2 \times 1.5714 = \mathbf{Rs.\ 3.1428}$$
   • Note: The Effective Spread (Rs. 3.14) is wider than the Quoted Spread (Rs. 2.00) because the large order size exhausted Tier 1 depth, walking the book into Tier 2.
2. Price Impact:
   $$\text{Price Impact} = P_{exec} - M = 352.5714 - 351.00 = \mathbf{Rs.\ 1.5714\ per share}$$
   • The institutional buy order pushed the market price up by Rs. 1.57 per share.

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(d) Regulatory Safeguards to Prevent Manipulation (5 Marks)

1. Circuit Breakers and Price Bands: Enforce index-wide circuit breakers (4%, 5%, 6% daily halts) and individual security dynamic price bands (maximum 2% fluctuation in 15-minute intervals) to halt pump-and-dump spikes.
2. Algorithmic Spoofing Surveillance: Implement automated order surveillance in NEPSE to detect spoofing (placing large non-genuine limit orders to deceive other traders and cancelling them milliseconds before execution).
3. Trade-to-Trade Settlement & Wash-Sale Filters: Block automated matching between identical Beneficial Owners across different brokerage accounts (preventing artificial volume inflation).
4. Enforcing Beneficial Ownership & Insider Trading Audits: Require company directors and major shareholders to declare holdings, barring trading during pre-earnings blackouts.