7.1 Market Organization, Orders, and Trading
Key Takeaways
- Financial markets support price discovery, provide liquidity, lower search and transaction costs, and allocate capital from savers to issuers.
- Primary markets raise new capital for issuers (IPO, seasoned offering, rights, private placement); secondary markets transfer existing securities among investors.
- Order-driven, quote-driven, and brokered markets differ in how trading interest is displayed and matched.
- Market, limit, stop, and stop-limit orders trade off execution certainty against price certainty; a stop becomes a market order, a stop-limit becomes a limit order.
- Tightness (spread), depth, resilience, and transparency are the four dimensions used to judge market quality and liquidity.
Why market structure matters
Equity investing begins with market organization. A security can be valuable in theory, but investors also need a practical way to buy, sell, clear, and settle it. Well-functioning markets perform six functions tested on the exam: they let savers borrow and lend, let firms raise equity, let investors hedge or speculate, support price discovery, provide informational efficiency, and lower search and transaction costs.
The primary market is where issuers sell new securities and receive capital. An initial public offering (IPO), seasoned equity offering, rights offering, or private placement belongs here. The secondary market is where investors trade securities already issued. Secondary trades do not deliver cash to the issuer, but deep secondary liquidity lowers the issuer's future cost of capital because investors pay more for shares they can later sell cheaply.
Participants and venues
Brokers act as agents for clients, seeking execution and earning commissions; they never take the other side. Dealers trade as principals from their own inventory, quoting a bid (the price at which they buy) and an ask (the price at which they sell). The bid-ask spread compensates dealers for order-processing costs, inventory risk, and adverse-selection risk (the risk of trading against a better-informed party). A market maker is a dealer obligated to post continuous two-sided quotes.
Exchanges are organized venues with listing rules and often a centralized limit order book. Over-the-counter (OTC) markets are dealer networks away from a central exchange. Electronic communication networks (ECNs) and alternative trading systems (ATS) match orders automatically; a dark pool is an ATS that hides pre-trade quotes to reduce market impact for large orders.
Markets are also classified by matching mechanism. Order-driven markets match public buy and sell orders using order-precedence rules (price priority first, then display, then time). Quote-driven (dealer) markets rely on dealers posting firm quotes. Brokered markets suit large, unique, or illiquid items (real estate, art, block trades) where a broker searches for a scarce counterparty.
Order types
A market order seeks immediate execution at the best available price: high execution certainty, low price certainty. In a thin book a market buy can "walk the book," filling at successively worse asks. A limit order sets the worst acceptable price (a buy limit caps the price paid; a sell limit floors the price received): better price control, but it may never fill, and a marketable limit can supply or take liquidity. A stop order activates only when the stop price is touched, then typically becomes a market order; a sell stop protects a long after a decline, a buy stop protects a short after a rise.
A stop-limit order becomes a limit order once the stop triggers, adding post-trigger price protection at the cost of fill certainty.
| Investor priority | Most likely order | Main risk |
|---|---|---|
| Must trade now | Market order | Poor execution price |
| Pay no more / sell for at least X | Limit order | No execution |
| Exit after an adverse price move | Stop (then market) | Triggered-fill price uncertainty |
| Exit with post-trigger price control | Stop-limit | No execution after trigger |
Market quality, short sales, and leverage
Liquidity has four dimensions: tightness (narrow spread), depth (size near the quote), resilience (fast price recovery after a trade), and transparency (visible pre- and post-trade data). A market can have a tight spread for small lots yet thin depth for blocks. A short seller borrows shares, sells them, and hopes to repurchase lower; risks include unlimited loss, dividend reimbursement to the lender, recall risk, and short squeezes. Buying on margin uses borrowed cash; the leverage ratio equals total position value divided by equity.
A margin call occurs when equity falls to the maintenance margin; the trigger price equals P0 × (1 − initial margin) / (1 − maintenance margin).
Validity conditions and execution instructions
Beyond the price instruction, orders carry validity conditions and execution instructions the exam tests. A day order expires at the close; a good-till-cancelled (GTC) order persists; an immediate-or-cancel (IOC) order fills what it can at once and cancels the rest; a fill-or-kill order demands a complete immediate fill or none; and market-on-open or market-on-close orders execute at the auction. Execution instructions such as all-or-nothing, hidden, or iceberg orders control how size is displayed.
A marketable limit order is priced aggressively enough to execute immediately — it takes liquidity like a market order while still capping price. A behind-the-market limit order rests in the book and supplies liquidity.
Worked leverage and short-sale numbers
Leverage cuts both ways. Suppose an investor buys 100 shares at USD 40 with 50% initial margin: position value is USD 4,000, equity is USD 2,000, and the loan is USD 2,000. If the price rises 10% to USD 44, the position is worth USD 4,400, equity rises to USD 2,400, and the return on equity is 20% — double the unlevered 10%, before interest. A 10% drop to USD 36 likewise doubles the loss to −20%.
For the short seller, the mechanics reverse: a short opened at USD 40 that the firm covers at USD 30 earns USD 10 per share less any borrow fee and dividends paid to the lender, but a rise to USD 60 produces a USD 20 loss with no theoretical ceiling — the source of the unlimited-loss caution.
Exam focus
Map the stem language: "must trade now" → market; "pay no more than" → limit; "activates after a trigger" → stop; "trigger plus price cap" → stop-limit. Separate roles cleanly — a broker is an agent, a dealer is a principal, a market maker is an obligated dealer. The "most liquid" market is tight, deep, resilient, and transparent, not merely high in share volume.
An investor wants to buy shares immediately and is willing to accept the best available price in the market. Which order is most appropriate?
A sell order that becomes a market order only after the stock trades at or below a specified trigger price is best described as a:
In an equity trade, a dealer most likely:
An investor buys stock at USD 50 with 50% initial margin and a 30% maintenance margin. A margin call occurs closest to a price of: