An investment banking mandate is the engagement letter that fixes the terms under which a bank will run your transaction — selling the company, raising capital, or restructuring debt. Success fees typically land between 1% and 5% of total transaction value depending on deal size, and the document around that fee controls scope, exclusivity, how long the bank keeps a claim on fees after the engagement ends, how either side can walk away, and who pays if something goes wrong. Read it before you sign it, because almost every term in a standard mandate is negotiated harder on the bank’s side than on yours.
What the Mandate Locks In
The scope section defines the job. In an M&A context, it says whether the bank represents the seller or the buyer. For a capital raise, it specifies whether the bank is placing debt, equity, or both, and under what method. The bank’s compensation and legal duties flow from this description, so vague scope language is a problem for both sides.
Most mandates are exclusive. You cannot hire another bank to run the same transaction during the contract period. Banks insist on this because the upfront investment is real: financial models, marketing materials, buyer outreach. Exclusivity periods typically run 6 to 12 months, with complex transactions running longer.
The tail provision is where companies get caught. If your company closes a deal with a party the bank introduced during the mandate, the bank collects its full success fee even if closing happens months after the engagement terminates. Twelve months is the most common tail period. This is one of the most heavily negotiated clauses in the agreement. Too long a tail locks you into paying the bank for deals it barely touched; too short lets a company run out the clock and cut the bank out of a deal it originated. The definition of “introduced” matters as much as the length. A broad definition can sweep in parties your company already knew before the engagement started, so the tail list should be a named, closed set of contacts the bank actually brought to the table.
What You’ll Pay
Bank compensation combines several pieces, and the mandate should price each one explicitly.
Retainer
Many banks charge an upfront or monthly retainer to cover preparation and early outreach. Middle-market retainers generally run $5,000 to $15,000 per month, or $30,000 to $100,000 as a lump sum. Some banks credit part of the retainer against the eventual success fee; others treat it as separate and non-refundable. If buyer interest in your company is strong, you have leverage to negotiate the retainer down or eliminate it.
Success Fee
The success fee is the larger number and it triggers only at closing. For M&A, it’s a percentage of total deal value. The original Lehman Formula still gets cited as a benchmark: 5% of the first $1 million, 4% of the second, 3% of the third, 2% of the fourth, and 1% of everything above $4 million. Most banks consider those percentages too thin for the work involved, so many firms now use a “Double Lehman” that roughly doubles each tier. Fees compress on larger deals. Transactions above $100 million often carry success fees of 1–2% of total value, while deals below $10 million can run 5–7%.
Many mandates include a minimum fee floor the success fee cannot drop below regardless of the final price. For larger advisory firms this minimum can exceed $1 million, which protects the bank if the deal closes at a lower valuation than planned.
Expenses
Travel, legal filing fees, data room subscriptions, and other out-of-pocket costs get reimbursed separately. Most agreements cap reimbursements at a specific dollar amount. Read the cap and the list of reimbursable categories. Some banks define expenses broadly enough to include costs you’d consider ordinary overhead.
FINRA Limits on Public Offerings
For public offerings only, FINRA Rule 5110 requires that total underwriting compensation not be “unfair or unreasonable.” The rule doesn’t set a single percentage cap, but it limits specific components: non-accountable expense allowances cannot exceed 3% of offering proceeds, and overallotment options (the “greenshoe”) are capped at 15% of the securities being offered.1Financial Industry Regulatory Authority. FINRA Rule 5110 – Corporate Financing Rule FINRA staff review filings before the offering proceeds and can block an offering if total compensation is excessive. This review applies only to public offerings. Private M&A advisory fees are not subject to it.
Firm Commitment Versus Best Efforts
If the mandate is for a capital raise rather than an M&A sale, the structure dictates who absorbs the risk of unsold securities, and that risk allocation drives the fee.
In a firm commitment underwriting, the bank buys the entire issuance from the company at an agreed price and resells it to investors. If demand falls short, the bank holds the leftover securities. Because the bank is taking real financial risk, underwriting fees are higher. The company gets certainty on proceeds.
In a best efforts arrangement, the bank markets the securities without guaranteeing a full sale. Unsold securities return to the company, and the company bears the shortfall risk. Fees are lower because the bank carries no inventory exposure. Best efforts arrangements are more common for smaller issuers.
How Either Side Walks Away
Every mandate should set out how either party can exit. Misreading these terms is where companies most often get hurt, because a poorly drafted exit clause can leave you paying a bank you’ve already fired.
Termination without cause typically requires 30 days’ written notice from either party. Some mandates demand 60 or 90 days, particularly if the bank is already deep into active marketing and needs time to wind outreach down.
Termination for cause allows immediate exit on material breach. Common triggers include the bank failing to perform agreed services or the company providing false financial data. Banks almost universally insist that their own liability be limited to gross negligence or willful misconduct as determined by a final court judgment. Ordinary mistakes, poor market timing, and deals that simply don’t close are not grounds for a claim against the bank under standard engagement letter terms.
The tail provision survives termination. Even after you fire the bank, you still owe the success fee on any deal that closes during the tail period with a party the bank introduced. Negotiating the length and the “introduced” definition before signing is far cheaper than litigating later.
Separate from the bank’s fees, the deal itself may carry breakup fees payable between buyer and seller if the transaction collapses. For M&A deals these cluster between 2% and 4% of deal value, with courts growing skeptical of fees above roughly 3% of the purchase price on the theory that higher fees discourage competing bids and interfere with the board’s duty to maximize shareholder value.
Who Bears the Risk if Something Goes Wrong
Standard mandates include an indemnification clause that shifts litigation risk to the company. If a lawsuit arises from information the company gave the bank (financial projections, customer data, regulatory disclosures) the company covers the bank’s legal costs and any resulting damages. The protection reaches third-party claims, including buyers who allege they relied on inaccurate data during the transaction.
The bank’s own liability runs the other way: narrowly drawn and heavily capped. Engagement letters confine the bank’s exposure to losses caused by its own gross negligence or willful misconduct. In practice, the bank faces essentially no financial liability for honest analytical errors, overly optimistic valuations, or disappointing outcomes. This asymmetry is one of the few areas where outside counsel reviewing a mandate consistently pushes back, and the pushback is worth the effort.
In significant M&A transactions, the bank may deliver a fairness opinion: a written assessment that the deal price is fair from a financial standpoint. It isn’t legally required, but Delaware courts have consistently treated receipt of a fairness opinion as strong evidence that the board fulfilled its duty of care in approving the transaction.2Financial Industry Regulatory Authority. Notice to Members 04-83 – Fairness Opinions Issued by Members For boards exposed to shareholder litigation, the opinion functions as a legal shield.
The obvious tension: the bank writing the fairness opinion usually earns a success fee contingent on closing, which creates an incentive to call almost any price fair. When a member firm has this kind of financial conflict in a public offering, FINRA Rule 5121 requires prominent disclosure of the conflict in the prospectus or offering document.3Financial Industry Regulatory Authority. FINRA Rule 5121 – Public Offerings of Securities With Conflicts of Interest Some boards hire a separate, independent firm for the fairness opinion, though that adds cost.
Does the Bank Have to Be Registered?
Federal law requires any firm that effects securities transactions to register as a broker-dealer with the SEC.4Office of the Law Revision Counsel. 15 USC 78o – Registration and Regulation of Brokers and Dealers Banks handling public offerings, debt placements, or equity issuances must maintain this registration and comply with FINRA membership and periodic examinations.
A significant exemption covers M&A brokers working exclusively with privately held companies. Under the same statute, an M&A broker is exempt from registration as long as it does not hold client funds or securities, does not facilitate transactions involving shell companies, does not provide deal financing, and does not represent both buyer and seller without written disclosure and consent from both sides.4Office of the Law Revision Counsel. 15 USC 78o – Registration and Regulation of Brokers and Dealers This covers much of the middle market, where boutique advisory firms sell private businesses without the full regulatory burden of a registered broker-dealer. If your transaction involves a publicly traded company or a registered securities offering, the exemption does not apply, and the mandate should name a registered firm.
Regulatory Filings You’ll Pay For
Certain transactions trigger mandatory government filings. The company, not the bank, typically bears these costs, so the mandate’s budget assumptions should account for them.
Hart-Scott-Rodino Premerger Notification
M&A deals above certain thresholds require premerger notification to the Federal Trade Commission and the Department of Justice. For 2026, the minimum reporting threshold is $133.9 million in transaction value. Both parties must observe a waiting period before closing. Filing fees start at $35,000 for transactions below $189.6 million and scale upward, reaching $2.46 million for deals valued at $5.869 billion or more.5Federal Trade Commission. New HSR Thresholds and Filing Fees for 2026 The threshold that applies is the one in effect at closing, not signing.
SEC Form D for Private Placements
If the transaction involves a private placement under Regulation D, the company must file a Form D notice with the SEC within 15 calendar days of the first sale, defined as the date the first investor becomes irrevocably committed to invest.6U.S. Securities and Exchange Commission. Filing a Form D Notice The SEC charges no fee for Form D, but the filing must go through EDGAR.7U.S. Securities and Exchange Commission. Frequently Asked Questions and Answers on Form D Most states impose their own notice filing fees for private placements, ranging from nominal amounts to a few thousand dollars.