Top 20 Mergers and Acquisitions Consulting Firms: Comprehensive Advisory for Strategic Success

1. McKinsey & Company

• Founders: James O. McKinsey
• Founded Year: 1926
• Headquarters: New York, New York, United States
• Product / Service Categories: Strategy consulting, M&A advisory & integration, portfolio transformation, capability building across due diligence, integration/separation, post‑merger value capture.
• Description: McKinsey & Company is widely regarded as one of the most influential global strategy consultancy firms. With origins in 1926 in Chicago (later expanding globally), it boasts deep expertise in steering large‑scale M&A activity – from target identification through integration, divestitures, and joint ventures. Its M&A practice emphasises rigorous analytic frameworks, proprietary tools (e.g., “Dealscan.AI”, “myIMO”), and a strong emphasis on value capture and culture compatibility.
• Key Features:
  • Proprietary analytic tools: e.g., Dealscan.AI, myIMO for M&A program management.
  • End‑to‑end M&A support: strategy, diligence, integration/separation, capability building.
  • Global reach and scale: offices worldwide, serving large complex transactions.
  • Strong emphasis on culture & operating‑model alignment post‑deal.
  • Thought leadership in M&A: frequent research and reports on deal trends.

2. Boston Consulting Group (BCG)

• Founders: Bruce Henderson
• Founded Year: 1963
• Headquarters: Boston, Massachusetts, United States
• Product / Service Categories: Corporate strategy, M&A strategy & integration, private equity advisory, commercial diligence, synergy capture.
• Description: BCG is a leading global management consulting firm with a strong M&A domain, particularly in strategy and integration phases. With a data‑driven approach and deep industry specialisation (for example in technology, media & telecom), BCG helps clients navigate complex transactions by aligning M&A action plans with long‑term corporate strategy, emphasising value creation rather than purely transaction execution.
• Key Features:
  • Rigorous data‑driven methodology in M&A strategy.
  • Strong industry‑vertical expertise, enabling sector‑specific insights.
  • Focus on integration and value‑capture beyond deal close.
  • Global footprint enabling cross‑border deal support.
  • Private equity and corporate advisory capability.

3. Bain & Company

• Founders: Bill Bain and others (originating from BCG alumni)
• Founded Year: 1973
• Headquarters: Boston, Massachusetts, United States
• Product / Service Categories: M&A consulting (strategy & execution), private equity deal support, integration and carve‑out management, value‑creation post‑deal.
• Description: Bain & Company is known for its strong focus on M&A for both corporate and private‑equity clients. Its approach emphasises building repeatable M&A capability within organisations, recognising that successful deals depend on disciplined processes and capability as much as on the transaction itself. According to its own materials, mastering disciplined M&A practices doubles success rates.
• Key Features:
  • Emphasis on capability‑building: helping clients execute M&A repeatedly.
  • Deep private equity experience, serving PE sponsors and portfolio companies.
  • Data and insight‑led approach: e.g., identifying “four key disciplines” in M&A.
  • Focus on value creation and exit readiness.
  • Balanced support across pre‑deal, deal and post‑deal phases.

4. PricewaterhouseCoopers (PwC)

• Founders: Samuel Lowell Price
• Founded Year: 1998 (current form, merger of Price Waterhouse & Coopers & Lybrand)
• Headquarters: London, England, United Kingdom
• Product / Service Categories: Audit & assurance, tax advisory, transaction services, M&A advisory, deal integration, carve‑out consulting.
• Description: PwC is part of the “Big Four” professional services firms and maintains a substantial M&A practice within its transactions and advisory line. It supports clients with deal strategy, due diligence, integration, and carve‑out/separation services – leveraging audit/tax strengths to offer holistic advisory during M&A events. Its global network spanning 157+ countries ensures robust cross‑border capability.
• Key Features:
  • Large global network enabling multi‑jurisdiction deals.
  • Integrated audit/tax/advisory offering, useful for complex transaction structures.
  • Strong in due diligence and financial‑deal fences (accounting, tax, compliance).
  • Full lifecycle support: strategy, execution, integration/separation.
  • Cross‑industry coverage, including mid‑market and large deals.

5. KPMG

• Founders: William Barclay Peat, James Marwick, Roger Mitchell, Piet Klijnveld, Jaap Kraayenhof, Reinhard Goerdeler
• Founded Year: 1987 (merger forming KPMG Peat Marwick)
• Headquarters: London, England, United Kingdom
• Product / Service Categories: Audit, tax, advisory; M&A deal advisory, transaction services, integration/separation consulting.
• Description: KPMG is another of the major global professional‑services networks with a strong M&A advisory arm. Within its advisory services, it provides support for companies through deal‑strategy, financial and tax due diligence, transaction structuring, post‑merger integration, and carve‑outs. Its broad professional services base gives it strength in complex compliance‑heavy transactions.
• Key Features:
  • Strong audit/tax/advisory backbone – helpful for deal risk mitigation.
  • Global footprint, enabling international M&A support.
  • Transaction services expertise: due diligence, structuring.
  • Integration and separation support tailored to deal‑complexity.
  • Industry‑specific teams handling regulatory‑sensitive sectors.

6. Ernst & Young (EY)

• Founders: Arthur Young and Alwin C. Ernst
• Founded Year: 1989 (merger of Ernst & Whinney and Arthur Young)
• Headquarters: London, England, United Kingdom
• Product / Service Categories: Assurance, tax, advisory; M&A advisory (transaction strategy, due diligence, integration), corporate finance.
• Description: EY is a global professional‑services firm with a strong M&A advisory offering. The firm assists clients with deal strategy, due diligence, post‑merger integration and carve‑outs, leveraging its broad advisory network. Often active in mid‑to‑large scale transactions, EY helps organisations realise value from deals, manage risk and execute complex structural work.
• Key Features:
  • Strong global advisory network across geographies.
  • Comprehensive transaction lifecycle support: strategy, deal, post‑deal.
  • Integrated audit/tax/advisory capabilities, helpful for deal‑risk mitigation.
  • Focus on value creation and integration execution.
  • Experience across sector‑specific deals (e.g., healthcare, tech, industrials).

7. Deloitte

• Founders: William Watt Deloitte
• Founded Year: 1845 (original firm)
• Headquarters: London, England, United Kingdom
• Product / Service Categories: Audit, consulting, tax, risk advisory; M&A consulting including transaction services, integration, carve‑outs, strategic advisory.
• Description: Deloitte is another major global player in the M&A consulting arena, combining its consulting and advisory capabilities with transaction‑services expertise. The firm helps clients with pre‑deal strategy, diligence, integration, separation and post‑deal value capture, often bridging business advisory with technology and operational integration.
• Key Features:
  • Broad consulting‑and‑transaction services mix.
  • Strong in technology integration and operational aspects post‑deal.
  • Global presence enabling cross‑border deals.
  • Able to handle large scale complex transformations tied to M&A.
  • Focus on synergy capture, cost‑take‑out and execution discipline.

8. A.T. Kearney (now “Kearney”)

• Founders: Andrew Thomas Kearney
• Founded Year: 1939 (origin)
• Headquarters: Chicago, Illinois, United States
• Product / Service Categories: Management consulting, corporate strategy, operations, M&A strategy & integration, private equity advisory.
• Description: Kearney is a global management‑consulting firm with considerable M&A advisory capability. Its focus is often on operational and commercial integration and value creation, helping clients translate strategy into action post‑deal. The firm has built a reputation for operating in complex corporate and private equity transactions, especially where operations and integration are critical.
• Key Features:
  • Strong operational and commercial integration expertise.
  • Private equity and corporate deal advisory capability.
  • Global footprint with regional specialists.
  • Focus on value‑creation beyond the transaction.
  • Deep industry sector specialisation in complex deals.

9. Oliver Wyman

• Founders: Firm founded as part of Marsh & McLennan
• Founded Year: 1984 (as Oliver Wyman)
• Headquarters: New York, New York, United States
• Product / Service Categories: Strategy consulting, risk/finance advisory, M&A advisory (especially in financial services & healthcare), integration, carve‑out.
• Description: Oliver Wyman is a global consulting firm particularly known for its expertise in financial services and insurance industries. In the M&A context, it offers advisory services in deal strategy, commercial & operational due diligence, integration planning, and risk management of transactions.
• Key Features:
  • Deep industry specialisation in financial services and healthcare.
  • Capabilities in risk, regulation and compliance within deals.
  • Mid‑market and large‑scale transaction advisory.
  • Focus on integration / value capture in regulated sectors.
  • Global presence with local expertise in deals across regions.

10. Accenture

• Founders: Originally the consulting division of Arthur Andersen; separated as Accenture in 2001.
• Founded Year: 2001 (as Accenture)
• Headquarters: Dublin, Ireland
• Product / Service Categories: Technology consulting, digital transformation, integration services, M&A technology enablement, post‑deal digital integration.
• Description: Accenture, a global professional services company, increasingly plays a strategic role in M&A consulting-particularly where technology, digital integration and transformation are central to the deal success.
• Key Features:
  • Strong digital and technology integration capability tied to M&A.
  • Global footprint with robust cross‑border delivery infrastructure.
  • Expertise in tech‑driven deals and digital carve‑outs.
  • Ability to execute large scale IT and operating‑model integration.
  • Value‑capture through digital operations post‑transaction.

11. Mercer

• Founders: Originally Mercer HR Consulting; now part of Marsh & McLennan
• Founded Year: 1945 (Mercer)
• Headquarters: New York, New York, United States
• Product / Service Categories: HR consulting, M&A people & talent integration, organisational design, post‑merger workforce management.
• Description: Mercer plays a vital role in the M&A consulting ecosystem: it focuses on the people, culture, and organisational side of transactions, making it a strategic partner for organisations where human capital risk is high.
• Key Features:
  • Expertise in people, culture and talent integration during M&A.
  • Focus on workforce design, retention strategy, and organisational health.
  • Post‑deal support to maximise human‑capital value.
  • Bridging HR consulting with transactional execution.
  • Strong presence in deals where talent is a critical asset.

12. Alvarez & Marsal

• Founders: Tony Alvarez II and Bryan Marsal
• Founded Year: 1983
• Headquarters: New York, New York, United States
• Product / Service Categories: Restructuring, turnaround, M&A integration & separation, performance improvement, transaction advisory.
• Description: Alvarez & Marsal is a specialist in deal‑environment consulting, especially in complex, turnaround, or restructuring environments.
• Key Features:
  • Strong in distressed or complex M&A environments.
  • Expertise in integration, separation, and operational turnaround.
  • Focused on performance improvement.
  • Hands‑on operational focus beyond pure strategy.
  • Value‑recovery and cost‑take‑out expertise post‑deal.

13. Slalom Consulting

• Founders: John McMahon and others
• Founded Year: 2001
• Headquarters: Seattle, Washington, United States
• Product / Service Categories: Strategy & transformation consulting, digital & technology integration, mid‑market M&A advisory, change & people enablement.
• Description: Slalom is a fast‑growing consulting firm known for its flexible, people‑centric approach and strong technology and digital integration capabilities.
• Key Features:
  • Mid‑market focus: agile, tailored advisory rather than mega‑deals only.
  • Strong technology and digital‑integration capability.
  • People‑centric change management and culture integration.
  • Value‑driven synergy frameworks and execution support.
  • Growing international presence.

14. Founders Advisors

• Founders: (Information limited)
• Founded Year: 2003
• Headquarters: Birmingham, Alabama, United States
• Product / Service Categories: Middle‑market M&A advisory, capital‑solutions consulting, sell‑side and buy‑side guidance for mid‑sized companies.
• Description: Founders Advisors is a specialist in middle‑market M&A, offering tailored advisory services to business owners looking to exit, grow, or acquire.
• Key Features:
  • Specialised in middle‑market transactions.
  • Strong in sell‑side advisory.
  • Capital‑solutions and growth‑acquisition support.
  • Sector‑focused expertise.
  • Boutique style – more customised attention.

15. Eton Venture Services

• Founders: (Information limited)
• Founded Year: 2008
• Headquarters: Austin, Texas, United States
• Product / Service Categories: Boutique M&A advisory for private equity firms, high‑net‑worth investors, mid‑market business exits.
• Description: Eton Venture Services is a boutique M&A advisory firm tailored to private equity and investor clients.
• Key Features:
  • Boutique size with agile decision‑making.
  • Private equity and investor‑focused advisory.
  • Mid‑market transaction experience.
  • Deep hands‑on support rather than large‑firm layers.
  • Transparent client engagement and customised deal‑structure support.

16. NMS Consulting

• Founders: (Information limited)
• Founded Year: (Information limited)
• Headquarters: United States
• Product / Service Categories: Management consulting, corporate advisory, strategic communications, tax advisory, M&A consulting (acquisition, divestiture, alliances & JVs).
• Description: NMS Consulting is a smaller but respected consultancy that combines strategic advisory, corporate communication, tax, and transaction services.
• Key Features:
  • Multidisciplinary advisory (strategy + communications + tax).
  • Versatility across acquisition, divestiture, alliances & JVs.
  • Ideal for clients seeking ‘one‑stop’ support across deal facets.
  • Boutique scale allows for personalised support.
  • Experience in both mid‑market and more complex transactions.

17. The Consulting Report

• Founders: (Information limited)
• Founded Year: (Information limited)
• Headquarters: (Information limited)
• Product / Service Categories: Insight, research, ranking of consultants and consulting firms (including M&A domain)
• Description: The Consulting Report provides valuable insight into the M&A consulting ecosystem by identifying top firms and leaders.
• Key Features:
  • Authority in consulting industry rankings & thought‑leadership.
  • Provides lists of top M&A consultants and leaders.
  • Insightful for benchmarking consulting‑vendor selection.
  • Helps selection of high‑performing firms in M&A advisory.
  • Useful as decision‑support resource rather than execution‑partner.

18. DealRoom

• Founders: (Information limited)
• Founded Year: (Information limited)
• Headquarters: United States
• Product / Service Categories: M&A software (due diligence, integration), consulting insights, vendor ranking of M&A consulting firms.
• Description: DealRoom offers M&A workflow software and consulting insights, acting as a useful resource for evaluating consulting partners.
• Key Features:
  • Offers M&A workflow software enabling integration & separation.
  • Acts as an advisory resource for firm‑selection.
  • Provides vendor comparisons and deal‑insight content.
  • Useful for buyers/sellers to evaluate consulting support.
  • Bridges technology and consultancy in M&A process‑execution.

19. Benchmark International

• Founders: (Information limited)
• Founded Year: (Information limited)
• Headquarters: United States
• Product / Service Categories: M&A advisory (middle‑market), business‑sales brokerage, transaction advisory, valuation and exit planning.
• Description: Benchmark International is a specialist mid‑market M&A advisory firm, providing tailored advisory to business owners looking to exit or grow through sale, acquisition or recapitalisation.
• Key Features:
  • Focus on middle‑market and privately‑held company transactions.
  • Exit‑planning