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Financial Due Diligence Services Companies in London – Complete Overview

This practical guide walks you through the financial due diligence services companies operating in London and how they help businesses navigate M&A transactions with greater confidence.

Rather than a strict ranking, this is an objective overview designed to give you clear context on who these companies are, how they operate, and the types of clients they typically support.

London is home to a diverse range of financial due diligence companies – from large international players with broad resources to more specialised teams that focus exclusively on transaction support. Each brings different strengths, experience levels, and approaches to analysing corporate structures, cashflow, tax positions, forecasts, and operational risks.

Whether you are preparing to buy or sell a business, understanding these companies will help you identify the right expertise for your specific transaction and make a more informed choice.

Acumon

Acumon is a London-based firm of chartered accountants providing specialist financial due diligence services to buyers, sellers and investors. The company supports mergers, acquisitions, disposals and investment transactions across the UK and internationally. Acumon focuses on delivering clear financial analysis and practical risk insights that help clients make better informed decisions.

The firm works with corporate groups, private equity houses, family offices and owner-managed businesses. Each due diligence engagement is tailored to the size, sector and complexity of the transaction. Acumon combines detailed financial review with commercial understanding gained from its own acquisition experience.

In addition to standard due diligence, the company supports both buy-side and vendor assignments. This allows clients to either validate a target or prepare their business for sale with greater confidence. Acumon’s approach emphasises clear reporting and actionable findings throughout the process.

Due Diligence Capabilities:

Acumon provides financial due diligence services across a wide range of transaction types and client situations. These include:

  • Buy-side due diligence for acquirers
  • Vendor due diligence for sellers
  • Mid-market corporate transactions
  • Private equity investments and exits
  • International group subsidiary reviews
  • SME and owner-managed business deals

Due diligence engagements are led by experienced professionals with direct senior involvement from planning to final reporting.

Regulatory Licences and Registrations:

Acumon operates with the following key professional registrations and compliance standards:

  • ICAEW chartered accountants registration
  • Registered audit firm
  • UK data protection and secure data room compliance
  • Professional indemnity insurance for transaction services

These registrations support the delivery of reliable due diligence work for both UK and cross-border transactions.

Core Services:

Acumon provides supporting services that strengthen transaction outcomes. These include:

  • Financial due diligence
  • Corporate structure and group analysis
  • Cash flow and working capital review
  • Forecast and quality of earnings assessment
  • Tax due diligence
  • Operational and strategic risk review
  • Post-transaction support

Due diligence work is often delivered alongside ongoing discussions with management teams and boards regarding key findings and risk mitigation.

Supporting M&A Transactions:

Acumon works with organisations at different stages of the transaction journey. The company supports clients who are:

  • Preparing for a business acquisition
  • Planning the sale of their company
  • Evaluating investment opportunities
  • Reviewing international subsidiaries
  • Seeking clarity on financial risks before completion

Early engagement helps ensure potential issues are identified and addressed efficiently.

Contact Information:

PwC UK

PwC supports buyers with financial due diligence during acquisition processes. The company examines financial, commercial, operational and strategic assumptions to help validate the rationale behind a potential deal. Their work focuses on understanding past performance to build a realistic view of future prospects and spot any hidden issues.

The approach includes detailed analysis of revenue streams, market conditions, maintainable earnings and future cash flows. PwC also reviews operational matters and potential synergies. This helps corporate and financial buyers gain clearer insight before committing to a transaction. The company works across different deal types and sizes in the London market.

Key Highlights:

  • Buy-side financial due diligence
  • Commercial and market analysis
  • Cash flow and earnings assessment
  • Operational issue review
  • Deal structuring support

Services:

  • Revenue due diligence
  • Synergy validation
  • Maintainable earnings analysis
  • Future cash flow projections
  • Commercial due diligence
  • Strategic assumption testing

Contact Information:

  • Website: www.pwc.co.uk
  • Phone: +44 (0)20 7583 5000
  • Email: laetitia.lynn@pwc.com
  • Address: 1 Embankment Place London WC2N 6RH United Kingdom 
  • LinkedIn: www.linkedin.com/company/pwc-uk
  • Facebook: www.facebook.com/PwCUK
  • Instagram: www.instagram.com/pwc_uk

EY

EY delivers due diligence through its EY-Parthenon team for mergers and acquisitions. The company combines financial review with commercial, operational and specialist assessments to give clients a rounded view of opportunities and risks. Their process supports both buyers and sellers in London and beyond.

EY examines historical financials, forecast assumptions and value drivers while integrating insights from other areas such as technology and people. The company uses data-driven methods to highlight normalisation adjustments and potential exposures. This integrated style helps clients make decisions with more clarity during transactions.

Key Highlights:

  • Financial and commercial due diligence
  • Operational and IT assessment
  • Buy-side and sell-side support
  • Data analytics integration
  • Risk identification focus

Services:

  • Historical financial analysis
  • Forecast evaluation
  • Working capital review
  • Commercial due diligence
  • Operational due diligence
  • IT and technology due diligence
  • Human resources due diligence

Contact Information:

  • Website: www.ey.com
  • Phone: +44 20 7951 2000
  • Address: 1 More London Place, London SE1 2AF
  • LinkedIn: www.linkedin.com/company/ernstandyoung
  • Facebook: www.facebook.com/EY
  • Twitter: x.com/EYnews

Deloitte

Deloitte provides transaction services with a strong emphasis on financial due diligence for acquisitions and disposals. The company supports both corporate clients and private equity teams throughout the deal process in London. Their teams focus on evaluating risks and opportunities that matter for decision making.

Deloitte works on acquisition due diligence and vendor support to help sellers present information clearly. The company brings together financial analysis with operational and commercial perspectives. This helps clients understand the full picture before completing a transaction.

Key Highlights:

  • Acquisition and vendor due diligence
  • Corporate and private equity focus
  • Integrated transaction support
  • Risk and opportunity evaluation

Services:

  • Financial due diligence
  • Commercial due diligence
  • Operational review
  • Working capital analysis
  • Vendor due diligence
  • Deal lifecycle support

Contact Information:

  • Website: www.deloitte.com
  • Phone: +44 (0)20 7936 3000
  • Address: 1 New Street Square London, EC4A 3HQ United Kingdom
  • LinkedIn: www.linkedin.com/company/deloitte
  • Facebook: www.facebook.com/deloitteuk
  • Twitter: x.com/deloitteuk

KPMG

KPMG offers deal advisory services that include due diligence for transactions. The company uses sector knowledge and analytical tools to examine targets from multiple angles. Their teams support clients in assessing value, risks and potential in the London market.

KPMG combines financial review with commercial, operational and technology perspectives. The company helps both buyers and sellers prepare for and navigate the due diligence process. Their approach aims to provide practical insights that inform deal decisions and negotiations.

Key Highlights:

  • Multidisciplinary due diligence
  • Sector specialist input
  • Data analytics support
  • Buy-side and sell-side work

Services:

  • Financial due diligence
  • Commercial due diligence
  • Operational due diligence
  • Technology due diligence
  • ESG due diligence
  • Value creation analysis

Contact Information:

  • Website: kpmg.com
  • Phone: +44 (0)20 7311 1000
  • Address: 15 Canada Square, Canary Wharf, London, E14 5GL
  • LinkedIn: www.linkedin.com/company/kpmg-uk
  • Twitter: x.com/kpmguk
  • Facebook: www.facebook.com/KPMG

BDO

BDO offers transaction services with a focus on due diligence for both buyers and sellers. The company supports clients through mergers, acquisitions, capital raises and other deals. Their work helps identify financial risks and opportunities while providing practical insights for decision making.

The team specialises in the mid-market segment and works with corporates, private equity houses and financial investors. BDO combines financial analysis with commercial and operational perspectives. This approach gives clients a clearer picture of underlying earnings, cash flows and potential issues. They also support post-transaction phases when needed.

Key Highlights:

  • Buy-side and sell-side due diligence
  • Mid-market transaction focus
  • Commercial and operational input
  • Post-deal support options

Services:

  • Financial due diligence
  • Commercial due diligence
  • Operational due diligence
  • IT due diligence
  • ESG due diligence
  • Working capital analysis

Contact Information:

  • Website: www.bdo.co.uk
  • Phone: 020 7486 5888
  • Address: 55 Baker Street London, W1U 7EU, United Kingdom
  • LinkedIn: www.linkedin.com/company/bdo-llp
  • Instagram: www.instagram.com/bdo_uk

Grant Thornton

Grant Thornton provides financial due diligence tailored to acquisition and investment decisions. The company examines historical performance, underlying profitability and key business drivers. Their process highlights trading patterns, working capital and potential red flags.

The team works closely with clients throughout the review and flags important findings early. Grant Thornton combines financial expertise with sector knowledge to support both corporate and private equity transactions in London and across the UK.

Key Highlights:

  • Underlying earnings focus
  • Sector knowledge integration
  • Early findings communication
  • Investment rationale support

Services:

  • Historical performance review
  • Working capital analysis
  • KPI and trading dynamics assessment
  • Cash and debt normalisation
  • Forecast assumption testing

Contact Information:

  • Website: www.grantthornton.co.uk
  • Phone: +44 (0)20 7383 5100
  • Email: malcolm.a.gomersall@uk.gt.com
  • Address: 8 Finsbury Circus London EC2M 7EA
  • LinkedIn: www.linkedin.com/company/grant-thornton-uk
  • Instagram: www.instagram.com/gt_trainees

Moore Kingston Smith

Moore Kingston Smith delivers due diligence support for buyers, sellers and investors. The company focuses on mid-market and SME transactions across various sectors. Their specialists provide practical advice throughout the transaction lifecycle.

The team works with trade buyers, private equity and family offices. Moore Kingston Smith helps assess financial risks and opportunities while supporting vendor preparation and negotiation. Their approach emphasises clear, actionable insights for each deal.

Key Highlights:

  • Mid-market and SME expertise
  • Full transaction lifecycle support
  • Buyer and vendor services
  • Sector-specific knowledge

Services:

  • Acquisition due diligence
  • Vendor due diligence
  • SPA advisory support
  • IT due diligence
  • Employee due diligence
  • ESG reporting review

Contact Information:

  • Website: mooreks.co.uk
  • Phone: +44 (0)20 4582 1000
  • Address: 6th Floor, 9 Appold Street, London, EC2A 2AP
  • LinkedIn: www.linkedin.com/company/moore-kingston-smith
  • Twitter: x.com/MooreKSLLP

Kreston Reeves

Kreston Reeves offers financial due diligence services from its London and South East offices. The company supports buyers, investors and funders with clear and concise reporting. Their reviews focus on performance, cash flows and key transaction risks.

The team tailors the scope to each deal, whether a high-level review or detailed analysis. Kreston Reeves works alongside other specialists when needed and helps clients make informed decisions with practical recommendations.

Key Highlights:

  • Tailored review scope
  • London and South East presence
  • Buyer and investor support
  • Practical recommendation focus

Services:

  • Pre-acquisition due diligence
  • Vendor due diligence
  • Pre-investment due diligence
  • Pre-lend due diligence
  • Financial performance review

Contact Information:

  • Website: www.krestonreeves.com
  • Phone: +44 (0)330 124 1399
  • Address: 2nd Floor, 168 Shoreditch High Street, London, E1 6RA
  • Twitter: x.com/KrestonReeves
  • LinkedIn: www.linkedin.com/company/kreston-reeves

PKF Littlejohn

PKF Littlejohn provides due diligence and advisory support for mergers, acquisitions, fund raises and sales. The company works with both experienced and newer leadership teams across London, Leeds and Manchester. Their process identifies risks and opportunities to support strategic decisions throughout the transaction.

The team delivers financial, tax, IT, ESG and regulatory due diligence with a hands-on approach. PKF Littlejohn also offers vendor support, transaction readiness reviews and completion accounts assistance. This helps clients prepare effectively and manage the deal from start to finish with clear insights.

Key Highlights:

  • Buyer and seller support
  • Multi-location UK presence
  • Hands-on senior involvement
  • Full transaction cycle help

Services:

  • Financial due diligence
  • Vendor due diligence
  • IT due diligence
  • ESG due diligence
  • Completion accounts review
  • SPA advisory support

Contact Information:

  • Website: www.pkf-l.com
  • Phone: +44 (0)20 7516 2200
  • Email: akonieczko@pkf-l.com
  • Address: 15 Westferry Circus, Canary Wharf, London E14 4HD
  • Twitter: x.com/PKF_Littlejohn
  • LinkedIn: www.linkedin.com/company/littlejohn
  • Instagram: www.instagram.com/pkf.littlejohn

Rayner Essex

Rayner Essex offers financial due diligence services from offices in London and Hertfordshire. The company supports both buyers and sellers with reviews of financial records, cash flows and projections. Their process helps parties understand the full picture during transactions.

The team works across different business sizes from sole traders to larger corporates. Rayner Essex provides a dedicated senior contact and focuses on clear communication. This makes the due diligence process more straightforward for clients preparing to buy or sell.

Key Highlights:

  • London and Hertfordshire base
  • Buyer and seller services
  • Fixed senior contact
  • Wide range of business sizes

Services:

  • Financial performance review
  • Cash flow examination
  • Balance sheet analysis
  • Buyer investigation support
  • Vendor preparation help
  • Deal process management

Contact Information:

  • Website: rayneressex.com
  • Phone: +44 (0)20 7388 2641
  • Email: th@rayneressex.com
  • Address: Tavistock House South, Tavistock Square, London, WC1H 9LG
  • LinkedIn: www.linkedin.com/company/rayner-essex
  • Facebook: www.facebook.com/rayneressexllp
  • Twitter: x.com/rayneressexllp
  • Instagram: www.instagram.com/rayneressex

Saffery

Saffery provides transaction services that include financial due diligence for acquisitions and sales. The company focuses on quality of earnings, working capital and debt analysis to give clients clearer deal insights. Their support covers both buy-side and vendor perspectives.

The team works with SMEs and owner-managed businesses across various sectors. Saffery delivers tailored reviews and vendor assistance to help address issues early. This helps reduce surprises and supports smoother transaction outcomes.

Key Highlights:

  • Quality of earnings focus
  • Vendor assistance options
  • SME transaction experience
  • Partner-led delivery

Services:

  • Financial due diligence
  • Vendor due diligence
  • Working capital analysis
  • Tax due diligence
  • Transaction support

Contact Information:

  • Website: www.saffery.com
  • Phone: +44 (0)330 094 3384
  • Email: info@saffery.com
  • Address: 71 Queen Victoria Street, London EC4V 4BE, UK
  • LinkedIn: www.linkedin.com/company/saffery
  • Instagram: www.instagram.com/saffery_uk

Mercer & Hole

Mercer & Hole supports clients with corporate finance and due diligence work as part of their wider services. The company advises on business acquisitions and provides insights into financial matters during transactions. Their London office serves clients considering purchases or sales.

The team delivers practical advice focused on understanding the financial position and potential risks in deals. Mercer & Hole works with businesses across different sectors and helps clients review information before completing transactions. This approach supports informed decision making throughout the process.

Key Highlights:

  • Corporate finance support
  • Acquisition advice
  • London office presence
  • Practical transaction insights

Services:

  • Financial due diligence
  • Business acquisition review
  • Transaction support

Contact Information:

  • Website: www.mercerhole.co.uk
  • Phone: +44 (0)20 7236 2601
  • Email: london@mercerhole.co.uk
  • Address: 3 Lombard Street, London, EC3V 9AA
  • LinkedIn: www.linkedin.com/company/mercer-&-hole
  • Facebook: www.facebook.com/Mercer-Hole-7615284227
  • Instagram:  www.instagram.com/mercerhole

S&W Group

S&W Group provides financial due diligence during transactions to give insights into past performance and future projections. The company identifies risks and helps clients understand key financial aspects before deals complete. Their work covers both buy-side and vendor situations.

The team tailors the scope to client needs and delivers clear findings on earnings, cash flows and controls. S&W also supports financing arrangements and offers SPA advice alongside due diligence. This helps clients make decisions with better information across various transaction types.

Key Highlights:

  • Tailored scope approach
  • Buy-side and vendor support
  • Clear reporting style
  • Financing due diligence

Services:

  • Historical performance review
  • Working capital analysis
  • Cash flow examination
  • Forecast assessment
  • Internal control review
  • SPA advisory support
  • Vendor due diligence

Contact Information:

  • Website: www.swgroup.com
  • Phone: +44(0)204 617 55 00
  • Email: legal@swgroup.com
  • Address: 45 Gresham Street, London EC2V 7BG
  • LinkedIn: www.linkedin.com/company/swgroupuk
  • Twitter: x.com/S_W_Group

Barnes Roffe

Barnes Roffe delivers financial due diligence to support business acquisitions and investment decisions. The company reviews historical results, forecasts and financial position to highlight potential risks. Their process aims to give buyers clearer understanding before purchase.

The team tailors reviews to the target company and funder requirements when needed. Barnes Roffe examines cash flows, assets, liabilities and accounting policies. This helps reduce surprises and supports negotiations during the acquisition process.

Key Highlights:

  • Tailored due diligence
  • Funder reporting options
  • Risk mitigation focus
  • Acquisition support

Services:

  • Historical results review
  • Cash flow analysis
  • Forecast examination
  • Balance sheet review
  • Tax due diligence
  • Financial systems assessment

Contact Information:

  • Website: barnesroffe.com
  • Phone: +44 (0) 20 8988 6100
  • Address: Leytonstone House, Leytonstone, London, E11 1GA
  • LinkedIn: www.linkedin.com/company/barnes-roffe
  • Instagram: www.instagram.com/barnesroffe

Light HC

Light HC offers due diligence and financial analysis services for investment and transaction decisions. The company provides detailed evaluations of financial information and business opportunities. Their work supports clients considering mergers, acquisitions or strategic moves.

The team focuses on risk identification and validation of financial data through balance sheet and cash flow reviews. Light HC delivers clear reports with actionable insights tailored to each engagement. This approach helps clients proceed with greater clarity on potential investments.

Key Highlights:

  • Investment review focus
  • Risk identification
  • Financial statement analysis
  • Customised reporting

Services:

  • Merger and acquisition due diligence
  • Financial statement analysis
  • Investment reviews
  • Risk identification
  • Detailed reporting

Contact Information:

  • Website: lighthc.london
  • Phone: +44 207 871 0485
  • Email: info@lighthc.london
  • Address: Fitzrovia, 60 Tottenham Court Road, London, W1T 2EW

RPG Crouch Chapman

RPG Crouch Chapman delivers buy-side and sell-side due diligence from its London office. The company provides insights into quality of earnings, working capital and cash flows for mid-market transactions. Their team supports private equity, corporates and lenders with clear findings.

The approach includes full scope or red-flag reviews depending on client needs. RPG Crouch Chapman maintains regular communication during engagements and offers vendor due diligence and SPA support. This helps clients understand risks and opportunities within agreed timescales.

Key Highlights:

  • Mid-market transaction focus
  • Buy-side and sell-side work
  • Flexible review options
  • Regular client updates

Services:

  • Quality of earnings analysis
  • Working capital review
  • Historical trading assessment
  • Forecast review
  • Vendor due diligence
  • SPA advisory support

Contact Information:

  • Website: www.rpgcrouchchapman.co.uk
  • Phone: 020 7870 9050
  • Email: hello@rpgcrouchchapman.co.uk
  • Address: 40 Gracechurch Street, London, EC3V 0BT
  • LinkedIn: www.linkedin.com/company/rpg-crouch-chapman-llp
  • Facebook: www.facebook.com/RPGCCAdvisers
  • Twitter: x.com/RPGCCAccounting
  • Instagram: www.instagram.com/rpgccadvisers

Conclusion

Choosing the right financial due diligence services company in London depends on several practical factors. These include the size and complexity of the transaction, the sector involved, the maturity of the target’s processes, and any specific regulatory requirements. Some companies offer a fully integrated multidisciplinary approach, while others provide more focused, specialist input on financial risks and controls.

The right partner delivers independent assurance and practical steps to reduce risks and support resilience. Ultimately, this guide offers a neutral overview of how different companies operate so you can compare them more effectively. With clearer context, it becomes easier to identify the team that best matches your transaction needs and working style.