SIE PREP | FINANCIAL REGULATION COURSES
A market maker is a broker-dealer firm that continuously quotes both a bid price — the price at which it will buy a security — and an ask price — the price at which it will sell — for a specified number of shares, standing ready to execute transactions on either side of the market at those prices and thereby providing the continuous liquidity that allows investors to buy and sell securities quickly without having to search for a willing counterparty.
The SEC defines a market maker as a firm that stands ready to buy and sell stock on a regular and continuous basis at a publicly quoted price. Market makers are the primary mechanism through which liquidity is created in securities markets, and their regulation, obligations, and role in price discovery are tested throughout the SIE and Series 7 examination curricula.
The Economic Function of Market Making
Every securities transaction requires a buyer and a seller to agree on a price at the same moment. In a world without market makers, a seller who wished to liquidate a position would need to wait — potentially for a long time — until a natural buyer appeared in the market at an acceptable price.
This waiting introduces uncertainty, delays, and the possibility that price gaps widen dramatically between transactions. Market makers solve this matching problem by interposing themselves continuously between buyers and sellers, holding inventory on their own balance sheets and standing ready to transact immediately on either side.
The market maker profits from the bid-ask spread — the difference between the price at which it buys and the price at which it sells. If a market maker quotes a stock at a bid of fifty dollars and an ask of fifty dollars and five cents, each round-trip transaction in which the market maker buys at the bid and sells at the ask generates five cents of gross revenue per share. This spread is the compensation the market maker receives for providing immediacy — the ability for investors to transact now at a known price rather than waiting for a natural counterparty.
The bid-ask spread is simultaneously the market maker's revenue and the investor's transaction cost. Narrow spreads indicate highly competitive, liquid markets in which multiple market makers compete vigorously for order flow. Wide spreads indicate less liquid markets with fewer competing market makers or with securities that carry higher inventory risk.
For large-cap equities with dozens of competing market makers, spreads of one cent — the minimum increment under Regulation NMS Rule 612 — are common. For thinly traded OTC securities with only one or two market makers, spreads of several percent may be typical.
The Two Regulatory Environments — Exchange Market Makers and OTC Market Makers
Market making in the United States occurs in two distinct regulatory environments, each governed by a different set of rules and obligations, and FINRA Rule 6320B and Rule 6420 define the two categories precisely.
Exchange market makers are registered with a national securities exchange — NYSE, Nasdaq, NYSE American, or others — for specific securities listed on that exchange.
On NYSE, the designated market maker — historically called the specialist — has specific affirmative obligations to maintain a fair and orderly market in assigned securities, including the obligation to quote within specified proximity to the national best bid and offer during market hours.
FINRA Rule 6320B defines an exchange market maker in the context of FINRA's trading rules as a member registered in a designated security as a market maker with an exchange or registered securities association.
OTC market makers operate in the over-the-counter markets, making markets in securities not listed on national exchanges — including OTC equity securities traded through FINRA's OTC trading systems. FINRA Rule 6420 defines an OTC market maker as a FINRA member that holds itself out as a market maker by entering proprietary quotations or indications of interest for a particular OTC equity security in any inter-dealer quotation system.
A firm is an OTC market maker only in those securities in which it actively displays market making interest — registering as a market maker in one security does not impose market making obligations in another.
Any firm conducting market making activity must first register as a broker-dealer with the SEC under Section 15 of the Securities Exchange Act of 1934, which makes it unlawful for any broker-dealer to effect transactions in securities using interstate commerce without registration. Market making activity additionally requires FINRA membership and registration in the specific securities in which the firm intends to make markets.
Quotation Obligations — The Two-Sided Quote Requirement
The defining regulatory obligation of a registered market maker is the requirement to maintain continuous two-sided quotations — both a bid and an ask — at firm prices during regular market hours. This continuous quotation commitment is what separates market makers from ordinary dealers who may choose when to offer to buy or sell. The market maker is obligated to trade at its quoted prices when orders arrive, up to the size of its quoted quotation.
Under Regulation NMS — specifically SEC Rule 602, the Firm Quote Rule — market makers and exchanges must honour their displayed quotes up to the displayed size. A market maker displaying a bid of fifty dollars for one thousand shares must buy up to one thousand shares at fifty dollars from any seller who presents an order. The firm quote obligation ensures that displayed prices are genuine and that investors can rely on them when routing orders.
The National Best Bid and Offer — universally abbreviated NBBO — is the consolidated best bid and best ask across all exchanges and trading venues at any given moment, computed from the quotations of all registered market makers and displayed by the securities information processors under Regulation NMS Rule 603. Regulation NMS Rule 611 — the Order Protection Rule — requires trading venues to prevent trade-throughs, ensuring that executions do not occur at prices inferior to the NBBO. Market makers are required to quote at the NBBO or better, meaning they cannot systematically quote inside the market — offering inferior prices while better prices are available at competing venues.
Market Maker Profit — The Spread and Inventory Risk
Market makers earn revenue from the bid-ask spread but bear significant inventory risk in the process. When a market maker buys a security at the bid, it adds that security to its inventory. If the price subsequently falls before the market maker can sell at the ask, it suffers a loss on the inventory position. Market makers therefore manage their inventories dynamically — adjusting bid and ask prices to attract order flow that reduces their inventory imbalances, widening spreads when inventory accumulates on one side to attract offsetting orders.
The revenue model depends critically on order flow — the volume of buy and sell orders that arrive at the market maker's quotes. High-frequency trading firms dominating modern equity market making compete on speed — their algorithmic systems can adjust quotes in microseconds in response to new information, allowing them to provide tight spreads while managing inventory risk through rapid repositioning rather than through wide spreads.
Citadel Securities, Virtu Financial, and similar electronic market making firms account for the substantial majority of quoted liquidity in United States equity markets, having largely displaced the traditional specialist and dealer systems that characterised markets before the widespread adoption of electronic trading. NYSE's paper on market making confirms that for the most active large-cap stocks with very deep order books, market making is effectively automated and competitive to the point where spreads reach the minimum one-cent increment regardless of market maker obligations.
Market Makers and the OTC Bulletin Board
In the OTC markets for smaller and less liquid securities — including OTC Bulletin Board securities and securities quoted on OTC Markets Group platforms — market makers play an especially critical role because there is no exchange providing a centralised order book and matching mechanism. The OTC market maker provides the only visible price for investors seeking to buy or sell these securities.
FINRA Rule 6460 requires OTC market makers displaying quotations in inter-dealer quotation systems to publish immediately bids and offers that reflect customer limit orders at better prices than the market maker's own displayed quotation, ensuring that customer price improvement is incorporated into the displayed market. This limit order display obligation prevents market makers from internalising customer orders at prices worse than those customers have specified while displaying only the market maker's own less competitive prices to the public.
Market Makers in the Options Market
The options market has its own market maker structure administered by the Options Clearing Corporation and the options exchanges — Cboe, NYSE American, Nasdaq PHLX, and others. Options market makers register in specific options classes and commit to quoting two-sided markets in those contracts during trading hours, providing the liquidity that allows options traders to open and close positions at displayed prices.
Options market makers manage significantly more complex risk than equity market makers because options positions create exposure across multiple dimensions — delta, gamma, vega, and theta — that must be hedged dynamically using the underlying stock and other options. The complexity of options market making requires sophisticated risk management systems and substantial capital.
Examination Relevance and Key Takeaways
Market makers are tested on the SIE, Series 7, and Series 65 examinations in the context of market structure, price discovery, the bid-ask spread, OTC markets, and the regulatory framework governing quotation obligations.
The key points to retain are these.
A market maker is a broker-dealer that continuously quotes both a bid and an ask price for a security, standing ready to buy at the bid and sell at the ask, providing liquidity by interposing itself between buyers and sellers rather than waiting for natural counterparties to match. Market makers profit from the bid-ask spread — the difference between the bid and the ask — and bear inventory risk from the securities they hold while waiting to complete the round-trip transaction.
All market makers must register as broker-dealers under Section 15 of the Securities Exchange Act of 1934 and must be FINRA members.
Exchange market makers are registered with specific national securities exchanges under FINRA Rule 6320B. OTC market makers are defined under FINRA Rule 6420 as FINRA members displaying proprietary quotations in OTC equity securities through inter-dealer quotation systems.
The Firm Quote Rule under Regulation NMS Rule 602 requires market makers to honour their displayed quotes at the displayed size when orders arrive. Regulation NMS Rule 611 — the Order Protection Rule — prevents trade-throughs by requiring that executions not occur at prices inferior to the NBBO, which consolidates the best bid and ask across all trading venues.
The bid-ask spread represents the market maker's gross revenue and the investor's transaction cost — narrower spreads indicate more competitive, liquid markets while wider spreads reflect greater inventory risk or less competition.
