What a Legal 'Red Flag' Report Is in Due Diligence

The problem it solves

Full legal due diligence on a company can run to hundreds of pages once every contract, lease, employment file, licence and piece of litigation has been reviewed. Almost nobody on the buyer’s side, whether a corporate development team, a private equity partner or a board, has time to read all of it before signing. The red flag report exists to bridge that gap. Instead of a document-by-document narrative, it pulls out only the issues that matter commercially and ranks them by severity, so decision-makers can see quickly what might derail the deal, what might cost money, and what can simply be filed away.

It is not a substitute for the underlying due diligence. Lawyers still review the data room in full. The red flag report is the distilled output, usually sitting alongside (or instead of) a longer full-form due diligence report, depending on how the deal is structured and how much the client is paying for.

What counts as a ‘red flag’

A red flag is any issue that could affect price, structure, timing or the buyer’s willingness to proceed at all. Common categories include:

• Change of control clauses in key contracts or leases that let a counterparty terminate or renegotiate if the target company is sold.
• Consents and approvals needed from regulators, landlords, lenders or joint venture partners before the deal can complete.
• Litigation and disputes, actual or threatened, that could create liabilities after completion.
• Employment issues, such as unresolved grievances, key person dependency, or terms that trigger costly obligations on a sale (for example enhanced redundancy rights).
• Title and ownership gaps, particularly around intellectual property, property leases, or shares that were never properly transferred.
• Regulatory or compliance failures, including anything that suggests the target has not been operating within its licence conditions or sector rules.
• Related party arrangements that were not on arm’s length terms and may unwind or need renegotiating post-completion.

Not every red flag is fatal. Lawyers typically grade issues using a simple system, often red, amber and green, or high, medium and low risk. A true red might be a live claim that could wipe out most of the target’s value or a change of control clause in the single most important customer contract. An amber might be a minor compliance gap that is easily fixed. The grading is what turns a list of findings into something a client can act on.

How it is used in the deal

A red flag report feeds directly into deal mechanics rather than sitting as background reading. The issues it raises typically get dealt with in one of a few ways:

• Price adjustment. A quantifiable liability, such as an unpaid tax exposure or an underfunded pension scheme, can be reflected in a lower purchase price or an escrow arrangement holding back part of the consideration.
• Warranties and indemnities. Issues that cannot be fixed before completion are often addressed through specific warranties, or a specific indemnity that shifts a defined risk back onto the seller if it crystallises later.
• Conditions to completion. A red flag that needs resolving before the deal can safely proceed, such as obtaining a third-party consent, can become a condition precedent that must be satisfied before signing or completion.
• Walking away. Occasionally the report surfaces something serious enough, a fundamental title problem or undisclosed litigation, that the buyer decides not to proceed at all.

Because the report directly shapes negotiation, timing matters. Lawyers usually try to get a first-cut red flag report to the deal team early, often before the full due diligence review is complete, precisely so that serious issues can be raised with the other side while there is still time to negotiate rather than after the transaction structure has been fixed.

Who reads it and how it is written

Red flag reports are written for a commercial audience, not for other lawyers. That means plain language, short summaries, and a clear separation between what the lawyers found and what they recommend doing about it. A well-written report will typically open with an executive summary of the handful of issues that genuinely need board-level attention, followed by supporting detail organised by topic (corporate, commercial contracts, property, employment, litigation, regulatory), with cross-references back to the relevant documents in the data room.

The scope of a red flag report is agreed at the outset of the engagement, since due diligence can be tailored to focus on particular areas depending on the sector and the deal. A buyer acquiring a care home group will want heavy scrutiny of regulatory compliance and staffing; a buyer acquiring a software business will focus more on intellectual property ownership and key customer contracts. The report reflects those priorities rather than attempting to cover everything with equal weight.

Limits of the exercise

A red flag report only covers what was disclosed and reviewed. It cannot flag what was hidden from the data room, and its usefulness depends heavily on how thorough and well-organised the disclosure process was in the first place. It is also a snapshot at a point in time, so deals with a long gap between signing and completion often involve updated due diligence, and an updated flag report, closer to completion.

Where to check further

For how solicitors’ due diligence work is regulated and the standards firms must meet, see the Solicitors Regulation Authority. For general guidance on M&A practice and standard market documentation, the Law Society is a useful starting point.