What an Investment Bank Actually Does, and Who Advised 2025's Biggest Deals

Strip away the films and the bonus headlines and an investment bank does three things for companies, governments and funds. It advises on transactions, it raises capital, and it makes markets in securities. Advisory means mergers, acquisitions, sales and takeover defences. Capital raising means underwriting shares (equity capital markets, or ECM) and bonds (debt capital markets, or DCM). Markets means sales, trading and research for institutional investors.

Most of the prestige, and most of the misunderstanding, sits in advisory. The bank does not buy the company. It builds the valuation, finds buyers or targets, runs the auction, negotiates alongside the lawyers and, in a public deal, often delivers the fairness opinion a board relies on. It is usually paid a success fee when the deal closes.

Three kinds of firm

• Bulge bracket: global universal banks such as Goldman Sachs, JPMorgan, Morgan Stanley, BofA Securities and Citi. They combine advice with a balance sheet, so they can lend, underwrite and trade around the same deal.
• Elite boutique: advice-only firms such as Evercore, Centerview Partners, PJT Partners and Lazard. No lending book, fewer potential conflicts and senior bankers close to the client; their pitch is independence.
• Middle market: banks and specialist advisers focused on small and mid-sized companies, often founder or family owned, where the buyer is frequently a private equity fund.

A league table measures the deals a bank touched, not the quality of its advice. Read it as a map of relationships.

Who advised the biggest deals of 2025

In Dealogic's full-year 2025 ranking of announced M&A, Goldman Sachs was first with $1,617.5 billion across 512 deals, a 31.8% share. JPMorgan followed with $1,355.9 billion and Morgan Stanley with $1,110.6 billion, then BofA Securities and Citi. Two boutiques broke into the top ten: Evercore, sixth with $542.6 billion, and Centerview Partners, seventh with $531.6 billion on just 118 deals. Barclays, Wells Fargo and UBS completed the list.

LSEG data, reported by Reuters on 6 January 2026, told the same story with different numbers. Goldman advised on $1.48 trillion of deals, including 38 of the 68 transactions worth $10 billion or more, and earned an estimated $4.6 billion in M&A fees, ahead of JPMorgan at $3.1 billion and Morgan Stanley at $3 billion. Data providers count deals differently, which is why their totals never match.

What to ask before you hire one

• Who will actually work on my deal, and how many similar transactions has that team closed?
• Does the bank lend to, or advise, likely buyers? How are conflicts disclosed and managed?
• How is the fee built: retainer, success fee, minimum fee, and what triggers each one?
• Will my deal need financing that only a full-service bank can provide, or is independent advice worth more?