Investment banks help companies raise capital through underwritten and privately placed offerings, and advise on mergers, acquisitions, sales and restructurings. In US law much of this is broker-dealer activity, which is why it is regulated. Firms range from global bulge-bracket banks to small advisory boutiques, and FINRA data show that most firms focused on M&A and investment banking are small.
In this lesson you will
- Define the core investment banking businesses: underwriting, private placement and M&A advisory.
- Explain why investment banking activity usually falls under broker-dealer regulation.
- Distinguish bulge-bracket, middle-market and boutique firms, and use FINRA data to describe the industry's size mix.
- Recognize when and why companies choose to use an intermediary at all.
A bank for companies, not for deposits
Despite the name, an investment bank is not where a company opens a checking account. It is a firm that helps companies and investors with big, infrequent financial events: raising money, buying or selling a business, merging with a rival or reorganizing a balance sheet. In US securities law, much of that work falls under the definition of a broker, meaning any person engaged in the business of buying or selling securities for the account of others, or a dealer, which does the same for its own account [1]. The SEC lists finding investors for companies or funding rounds, and finding buyers and sellers of businesses, among the activities that can require broker-dealer registration [1].
The core businesses
FINRA describes the investment banking representative's job as advising on or facilitating debt or equity offerings, whether through a private placement or a public offering, and mergers and acquisitions [2]. The FINRA exam for that role is organized around three functions: collecting, analyzing and evaluating data; underwriting and new financing transactions; and mergers and acquisitions, tender offers and financial restructurings [3].
- Underwriting public offerings. The SEC describes underwriters as the investment banks that manage and sell an IPO for the company [4]. Before the registration statement becomes effective, underwriters gather indications of interest from prospective investors and use them to recommend a price, which the issuer ultimately decides [4].
- Placing private offerings. In a private placement the bank usually acts as placement agent: it drafts the engagement documents and placement agent agreement, identifies suitable investors, and prepares materials such as a private placement memorandum, a teaser and term sheets [3].
- Sell-side M&A advisory. When a client wants to sell, bankers negotiate the engagement letter, value the business, analyze potential buyers, prepare marketing materials and run the bidding process [3].
- Buy-side M&A advisory. When a client wants to acquire, bankers assess the target, build valuations using methods such as comparable companies, precedent transactions and discounted cash flow analysis, and help develop and negotiate bids [3].
- Fairness opinions and restructuring. Bankers may prepare the financial analysis behind a fairness opinion [3]; FINRA Rule 5150 requires specific disclosures, including any compensation contingent on the deal closing, when that opinion will be provided or described to public shareholders [7].
Distribution is part of the value. The SEC notes that underwriters and dealers often distribute most IPO shares to institutional and high-net-worth clients such as mutual funds, hedge funds, pension funds and insurance companies [4]. A bank's relationships with buyers of securities, or buyers of companies, are a large part of what an issuer is paying for.
Do companies need an intermediary?
Not always. A company selling its own securities generally is not acting as a broker, and its employees may rely on a narrow "issuer's exemption" for limited selling work [1]. In practice, many private raises never involve a bank: a FINRA economist study of Form D filings found that only about 10% of Regulation D offerings in its 2013 to 2022 sample identified a financial intermediary [6]. Broker-dealer involvement depended mainly on industry, highest for energy and real estate issuers and lowest for technology issuers and venture capital funds, and broker-dealers tended to participate in larger deals [6]. The authors interpret this as issuers weighing the benefit of finding qualified investors and cutting search costs against the cost of hiring a broker-dealer [6].
Bulge bracket, middle market and boutique
These are industry nicknames, not legal categories. "Bulge bracket" generally refers to the largest global banks, which combine advisory work with large underwriting, trading and lending businesses and typically lead the biggest IPOs and mergers. "Middle-market" banks generally focus on mid-sized companies and transactions, often with deep sector specialization. "Boutiques" are smaller independent firms that tend to concentrate on advice, such as M&A, capital raising and restructuring, rather than balance-sheet businesses.
FINRA's data give a sense of the landscape. FINRA classifies member firms as small (1 to 150 registered representatives), mid-size (151 to 499) or large (500 or more), and at year-end 2025 it counted 2,832 small, 197 mid-size and 155 large firms, 3,184 in total [5]. In FINRA's business-model breakdown as of December 2025, 693 small firms fell in the "M&A and Investment Banking" segment, compared with 11 mid-size and 7 large firms [5]. FINRA also oversees Capital Acquisition Brokers, a category whose rules took effect in 2017 for firms with a limited range of activities, including advising companies on capital raising and corporate restructuring and acting as placement agent for sales of unregistered securities to institutional investors under limited conditions [5].
Key terms
- Broker
- A person engaged in the business of buying or selling securities for the account of others; generally must register with the SEC.
- Dealer
- A person engaged in the business of buying or selling securities for its own account.
- Underwriter
- An investment bank that manages and sells a securities offering, such as an IPO, for the issuing company.
- Placement agent
- A broker-dealer that finds and solicits investors for a private (unregistered) offering on the issuer's behalf.
- Sell-side / buy-side advisory
- M&A advice to a company being sold (sell-side) or to an acquirer (buy-side).
- Bulge bracket
- Informal label for the largest global investment banks with full underwriting, trading and advisory platforms.
- Boutique
- Informal label for a smaller, often independent firm focused mainly on advisory work.
- Capital Acquisition Broker (CAB)
- A FINRA member category, effective 2017, limited to activities such as capital-raising and restructuring advice and certain institutional placements.
Check your understanding
Sources
- [1]U.S. Securities and Exchange Commission, “Broker-Dealers,” April 24, 2026.
- [2]FINRA, “Series 79 – Investment Banking Representative Exam,” Accessed November 2026.
- [3]FINRA, “Investment Banking Representative Qualification Exam (Series 79) Content Outline,” 2025.
- [4]U.S. Securities and Exchange Commission, Office of Investor Education and Advocacy, “Investor Bulletin: Investing in an IPO,” February 2013.
- [5]FINRA, “2026 FINRA Industry Snapshot,” September 2026.
- [6]FINRA Office of the Chief Economist, “The Roles of Broker-Dealers in Regulation D Offerings, 2013-2022,” January 24, 2025.
- [7]FINRA, “5150. Fairness Opinions,” Accessed November 2026.
Educational content only — not legal, tax, or investment advice, or an offer to sell or a solicitation of an offer to buy any security. Rules and data are described as of November 2026 and may change. Securities offered through Umergence LLC, Member FINRA/SIPC.