The World’s Top Mergers & Acquisitions Consulting Firms

Fundamentally, M&A is a process of consolidation where companies acquire partial or complete control over another through various financial transactions, including divestitures, asset purchases, capital raising, consolidations, joint ventures, buyouts, and more. The significance of M&A as a growth strategy cannot be overstated, with the international deal volume attaining $549 billion in revenue thus far in 2024, an 8% increase from 2023's first quarter, which ultimately resulted in a total of $3.2 trillion. The complexity of these global M&A deals drives the demand for professional services and specialized deal-making expertise offered by management consultants. These M&A advisors facilitate the world’s largest business transactions each year. They’re responsible for providing buy-side and sell-side advisory services and executing and managing the entire M&A process, from deal origination to post-merger integration.

The Big Four

While we’ve created this list with no order in mind, the following firms are known to the industry as the “Big Four,” representing the largest professional services networks globally.

Deloitte

‍Deloitte is the largest of the Big Four and provides a wide range of services, including audit, consulting, financial advisory, risk management, and tax services.

Deal Volume: According to a report by LSEG, Deloitte advised on 361 mid-market deals valued at $7.1 billion.

Average Deal Size: Deloitte’s deal size is typically large, given its involvement in megadeals across various industries.

Geographic Footprint: Headquartered in London, the firm has a strong global presence in the Americas, Europe, Middle East, Africa (EMEA), and Asia-Pacific (APAC), with offices in over 150 countries.

Service Specialties: Deloitte is known for its comprehensive M&A services, including deal advisory, due diligence, post-merger integration, and restructuring.

Landmark Transactions: Deloitte has been involved in numerous high-profile deals in the technology, healthcare, and financial services sectors. In 2023, they completed a $11.6 billion acquisition of Biohaven Pharmaceuticals by Pfizer, one of the industrial sector’s most significant deals for the year.

PwC (PricewaterhouseCoopers)

PwC is another Big Four firm known for its financial, operational, and strategic M&A consulting services.

Deal Volume: Similar to Deloitte, PwC manages substantial deal volumes across many industries. In 2023, they provided services for 675 transactions, earning $16.7 billion in total deal value.

Average Deal Size: PwC Consultants can expect to work on mid-market to large-scale transactions.

Geographic Footprint: Also based in London, The firm operates globally to serve its vast client base, with over 280,000 employees and locations in over 150 countries.

Service Specialties: PwC excels in M&A strategy, financial due diligence, and post-deal services, specializing in complex global transactions with a strong emphasis on compliance and regulatory issues.

Landmark Transactions: PwC has been a key advisor in extensive technology and healthcare mergers. Remarkably, two deals accounted for almost 25% of the revenue generated in 2023: Chevron’s $53 billion mega-deal acquisition of Hess Corporation and Exxon’s $59.5 billion acquisition of Pioneer Natural Resources. Through PwC’s advisory, Exxon cemented its position as the dominant force in North American energy resources.

KPMG

Like its peers, KPMG has a strong M&A practice. It provides end-to-end transaction support for due diligence, valuation, separation, and integration services and regularly advises on headline M&A transactions.

Deal Volume: KPMG continued its legacy as a leading financial adviser for 424 mid-market deals worth about $6.2 billion.

Average Deal Size: The firm focuses on a wide range of deals, from mid-to-large market deals.

Geographic Footprint: KPMG is based in Amstelveen, Netherlands, and operates in 157 countries. They have a solid presence in Europe and North America.

Service Specialties: It is mainly known for its work in deal advisory, audit and assurance, risk management, and business strategy. They are significant in the energy, automotive, and industrial sectors.

Landmark Transactions: One of KPMG’s most notable transactions in 2023 was the $5.4 billion sale of Chelsea FC to Clearlake Partners, the second largest ever for a sports franchise.

EY (Ernst & Young)

Rounding out our Big Four, Ernst & Young offers a full suite of M&A services, from strategy and origination to post-merger integration.

Deal Volume: EY’s volume is substantial. It consulted on 292 transactions, earning $6.3 billion in total deal value.

Average Deal Size: EY predominantly advises mid-to-large deals.

Geographic Footprint: The London-based firm has an extensive reach across all major regions with a global network that facilitates many cross-border deals.

Service Specialties: EY provides excellent audit, advisory, tax, and transaction advisory services. It prioritizes entrepreneurs and innovation, often working with startups and fast-growing market companies.

Landmark Transactions: EY is a key advisor for numerous mergers in healthcare, life sciences, technology, and consumer products. In 2023, they helped close Pfizer’s $43 billion acquisition of Seagen.

Slalom

Slalom, a DealRoom partner, offers tailored solutions to help organizations address their unique challenges and achieve sustainable growth. The consulting firm’s approach to M&A is value-focused, people-centric, and technology-enabled.

Deal Volume: Slalom’s deal volume is smaller than the Big Four but is growing rapidly.

Average Deal Size: Slalom excels in mid-market transactions.

Geographic Footprint: The Seattle-based firm primarily operates in North America but is expanding its international presence.

Service Specialties: The firm focuses on M&A advisory, digital transformation, and technology integration, implementing a world-class, value-based synergy framework.

Landmark Transactions: Slalom has provided notable services for its advisory roles in tech and digital transformations. The firm is a prolific innovator in deploying technology and AI solutions through partnerships with technology giants like AWS, Microsoft, Google, and Salesforce.

McKinsey & Company

Considered the most prestigious consulting firm, McKinsey has been the subject of endless articles, books, and even SEC investigations.

Deal Volume: McKinsey doesn’t report these metrics, but we can presume the value is high, particularly in strategic advisory for large-scale mergers.

Average Deal Size: The firm is famously secretive about the client list, but it’s known for its work on large and complex high-value transactions.

Geographic Footprint: Located in New York, McKinsey operates globally and has a strong presence in the Americas, Europe, and Asia.

Service Specialties: McKinsey is known for its strategic advisory in M&A, concentrating its efforts on helping clients realize synergies and achieve long-term value creation.

Landmark Transactions: The firm is involved in major deals in the technology, healthcare, industrial, and energy sectors.

Boston Consulting Group (BCG)

‍BCG is a leading management consulting firm that focuses on M&A strategy and integration. Like many of the consulting firms on this list, it tends to benefit from a large alumni network at major US corporations, which calls on BCG to help with various transactions.

Deal Volume: Like McKinsey, its volume is significantly high in strategic advisory.

Average Deal Size: The firm consults on large and often industry-shaping mergers.

Geographic Footprint: Headquartered in Boston, its namesake, BCG, has a global presence in North America and Europe.

Service Specialties: Known for its data-driven approach and deep industry expertise, BCG often advises on high-profile, complex deals in industries like technology, media, and telecommunications.

Landmark Transactions: BCG is critical in many transformative deals within the technology and industrial sectors. In 2021, it advised on Triton’s acquisition of Bergman Clinics.

Bain & Company

Bain’s expertise in M&A advisory for private equity and corporate clients makes it one of the leading PE firms in the USA. Two Bain & Company consultants, David Harding and Sam Rovit, wrote the book “Mastering the Merger,” considered one of the best on mergers and acquisitions.

Deal Volume: Bain’s deal volume primarily consists of private equity and strategic mergers.

Average Deal Size: The firm works on large deals and has a strong track record of helping clients achieve successful exits.

Geographic Footprint: The Boston-based firm operates internationally with locations in the Americas and Europe.

Service Specialties: Bain is particularly active in the consumer products, healthcare, and financial services sectors, facilitating due diligence, merger integration, and value creation.

Landmark Transactions: Bain has consulted on substantial private equity transactions, partnering with BCG on Triton’s acquisition of Berman Clinics.

Accenture

Accenture is a global professional services company that provides M&A consulting focusing on technology integration and transformation.

Deal Volume: The company’s deal value is high, especially in digital and technology-driven M&A.

Average Deal Size: Accenture excels in mid-to-large deals.

Geographic Footprint: Located in Dublin, Ireland, Accenture has a global reach and robust capabilities in digital markets.

Service Specialties: The company’s services encompass technology-driven M&A, digital transformation, and IT integration.

Landmark Transactions: Accenture is a key player in numerous technology and telecommunications mergers.

Oliver Wyman

Oliver Wyman offers specialized M&A consulting services, particularly in the financial services and healthcare industries.

Deal Volume: The firm’s deal volume is moderate, focusing on specialized industries.

Average Deal Size: Oliver Wyman primarily works on mid-market deals.

Geographic Footprint: Based in NYC, the firm has a strong presence in the USA and Europe but operates globally.

Service Specialties: Oliver Wyman’s M&A practice handles financial services, healthcare, risk management, and strategy.

Landmark Transactions: The firm takes on advisory roles in financial services mergers.

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‍Goldman Sachs

New York’s Goldman Sachs, a permanent fixture of the leading global investment banks, advised on M&A transactions worth over $858.8 billion in 2023, including several mega-deals. The highlight of these transactions was its advisory role in the merger between UnitedHealth Group and Change Healthcare, a deal valued at over $13 billion.

Morgan Stanley

The NYC-based firm Morgan Stanley advised on deals valued at $674.1 billion in 2023, including three mega-deals, each worth over $10 billion. In one of the most high-profile deals of the year, Morgan Stanley offered its services to Elon Musk during his infamous $44 billion acquisition of Twitter. This transaction helped Morgan Stanley maintain its strong position in the M&A advisory market.

JPMorgan Chase & Co.

Also located in New York, JP Morgan Chase remains dominant within the M&A landscape. In 2023, it consulted on transitions worth $636.9 billion. JPMorgan led the market regarding deal value in the first half of 2023 with several billion-dollar transactions, including the merger of two major European pharmaceutical companies valued at over $10 billion.

Citi (Citigroup)

New York’s Citi stands out as one of the major merger consulting firms, with deal volumes of $417.1 billion. In 2022, the bank managed the $27 billion merger between Kroger and Albertsons and the staggering $69 billion acquisition of VMWare by Broadcom, solidifying its position in the technology sector.

Bank of America Merrill Lynch (BofA Securities)

Last but certainly not least is NYC’s Bank of America Merrill Lynch, which reached $404.7 billion in deal value. One highlight of 2019 was its role in Bristol-Myers Squibb’s $74 billion acquisition of Celgene, a potential game-changing deal for Big Pharma. The bank’s M&A consultants also advised on LVMH’s $16 billion acquisition of Tiffany & Co. in 2020, emphasizing its ability to work across various industries.

Choosing the right M&A consulting company

While M&A consulting companies may seem like black boxes when retrieving any information, they’re usually not slow about putting together comprehensive pitch decks on their offerings if you have a good strategy or transaction proposition.

Ensure that your company approaches a few different consulting companies before deciding which M&A team to hire for your process.

Issues to look out for include:

• Relevant transactions in your industry some text
  • M&A consultants with relevant corporate finance industry experience generally bring more value than those without. These firms possess industry knowledge, understand the regulatory environment, and have relationships with key stakeholders.
• Project scope as outlined in the pitchsome text
  • Understanding the project scope outlined in the merger and acquisition consultants’ pitch is essential. It clarifies responsibilities around specific tasks, timelines, and deliverables and ensures that all specific elements of the transactions are covered.
• Costs involved (including contingencies)some text
  • Costs shouldn’t be the only consideration, but the reality is that they cannot be ignored. While deal commissions will tend to be relatively similar across the board, retainer fees are not. Deals can take time, so ensure at the outset that you’re comfortable paying retainer fees throughout the deal’s lifetime.

How DealRoom and the Right Consulting Firm Is a Winning Combo

All the M&A consulting firms have one thing in common: They’re only as good as their M&A consultants and the tools they use.

Many merger consultants leverage DealRoom, the investment banker’s M&A project management tool of choice. By underpinning M&A consulting firms with DealRoom’s market-winning M&A platform, you maximize your transaction’s deal of success and significantly enhance the efficiency with which transactions close.

Contact us today to learn how our project management platform can help you achieve outstanding mergers and acquisitions outcomes.