Deloitte
Global professional services network and Big Four accounting firm.
Michal Klajban · CC BY-SA 4.0
Deloitte is a global professional services network with its headquarters in London, England. By both revenue and employee count, it is the largest such network in the world, and it ranks among the Big Four accounting firms, the others being EY, KPMG, and PwC. The network operates through member firms of Deloitte Touche Tohmatsu Limited, a private company limited by guarantee that is registered in England and Wales.
The firm was started in London in 1845 by accountant William Welch Deloitte. It expanded into the United States in 1890. In 1952, it merged with Haskins & Sells to become Deloitte Haskins & Sells, and in 1989 it merged with Touche Ross in the US to form Deloitte & Touche. The international organization was renamed Deloitte Touché Tohmatsu in 1993, later shortened to Deloitte. In 2002, Arthur Andersen’s UK practice, along with several of that firm’s practices in Europe, North America, and South America, agreed to merge with Deloitte. Later acquisitions included Monitor Group, a large strategy consulting business, in 2013.
Deloitte provides audit, consulting, financial advisory, risk, tax, and legal services. It employs roughly 470,000 people globally and operates in more than 150 countries. In fiscal year 2024, the network reported aggregate revenues of US$67.2 billion. The firm has sponsored various activities and events, including the 2012 Summer Olympics.
In 2017, Deloitte suffered a major cyberattack that led to a breach of client confidentiality and the public exposure of a significant amount of employee information. The firm has also faced litigation concerning several of its audits. In 2023, Deloitte was the fourth-largest privately owned organization in the United States and has consistently appeared on Fortune magazine’s list of the 100 Best Companies to Work For.
**History**
**Early history** William Welch Deloitte opened an office on Basinghall Street in London in 1845. He became the first person appointed as an independent auditor of a public company, the Great Western Railway. In 1880, he opened an office in New York. The firm was based at No. 4 Lothbury in London from 1855 until 1905, when it moved to No. 54 London Wall Buildings. In 1890, Deloitte opened a branch office on Wall Street, managed by Edward Adams and P.D. Griffiths, marking its first overseas venture. Other branches soon opened in Chicago and Buenos Aires. In 1898, P.D. Griffiths returned from New York and became a partner in the London office. In 1896, Charles Waldo Haskins and Elijah Watt Sells formed Haskins & Sells in New York, later described as the first major US auditing firm established by American rather than British accountants. In 1898, George Touche opened an office in London, and in 1900, he joined John Ballantine Niven to establish Touche Niven at 30 Broad Street in New York.
On 1 March 1933, Colonel Arthur Hazelton Carter, President of the New York State Society of Certified Public Accountants and managing partner of Haskins & Sells, testified before the U.S. Senate Committee on Banking and Currency. His testimony helped persuade Congress that independent audits should be mandatory for public companies.
In 1947, Detroit accountant George Bailey, then president of the American Institute of Certified Public Accountants, launched his own firm. It grew quickly, and within less than a year, the partners merged with Touche Niven and A. R. Smart to form Touche, Niven, Bailey & Smart. Under Bailey, the organization expanded rapidly, partly by creating a dedicated management consulting function. It also strengthened ties with organizations founded by George Touche: the Canadian firm Ross and the British firm George A. Touche. In 1960, the firm was renamed Touche, Ross, Bailey & Smart, and became Touche Ross in 1969. In 1968, Nobuzo Tohmatsu formed Tohmatsu Aoki & Co in Japan, which joined the Touche Ross network in 1975. In 1972, Robert Trueblood, Chairman of Touche Ross, led the committee that recommended establishing the Financial Accounting Standards Board.
Meanwhile, Deloitte’s head office moved to 128 Queen Victoria Street in London in September 1964. In 1952, Deloitte’s firm (then known as Deloitte, Plender, Griffiths & Co.) merged with Haskins & Sells to form Deloitte Haskins & Sells.
In 1989, Deloitte Haskins & Sells merged with Touche Ross in the US to form Deloitte & Touche, led jointly by J. Michael Cook and Edward A. Kangas. A smaller number of Deloitte Haskins & Sells member firms, led by the UK partnership, rejected the merger with Touche Ross and soon merged with Coopers & Lybrand to create Coopers & Lybrand Deloitte (which later merged with Price Waterhouse to become PwC). Some Touche Ross member firms also rejected the merger and merged with other firms. In the UK, Touche Ross merged with Spicer & Oppenheim in 1990.
**Recent history** Because the US-led mergers created Deloitte & Touche, the firm’s name posed a problem: no single entity held worldwide exclusive rights to the names “Deloitte” or “Touche Ross,” as key member firms like Deloitte in the UK and Touche Ross in Australia had not joined the merger. The name DRT International was chosen, standing for Deloitte, Ross and Tohmatsu. In 1993, the international firm was renamed Deloitte Touche Tohmatsu.
In 1995, the partners of Deloitte & Touche decided to create Deloitte & Touche Consulting Group (now Deloitte Consulting). In 2000, Deloitte acquired Eclipse to add internet design to its consulting capabilities; Eclipse was later split into Deloitte Online and Deloitte Digital. In 2002, Arthur Andersen’s UK practice, the firm’s largest practice, along with several of its practices in Europe and North and South America, agreed to merge with Deloitte.
Lore & Background
Deloitte is a multinational professional services network headquartered in London, England, and is the largest such network globally by both revenue and headcount. It is one of the Big Four accounting firms, alongside EY, KPMG, and PwC. The network is structured as a collection of member firms under Deloitte Touche Tohmatsu Limited, a private company limited by guarantee. Its defining characteristics include a vast global footprint, operating in over 150 countries with approximately 470,000 employees, and providing audit, consulting, financial advisory, risk, tax, and legal services. In fiscal year 2024, the network reported aggregate revenues of US$67.2 billion. The firm’s origins trace to 1845, when William Welch Deloitte opened an office in London and later became the first independent auditor of a public company, the Great Western Railway. It expanded to the United States in 1890, opening a Wall Street branch. Key mergers shaped its modern form: a 1952 union with Haskins & Sells, a 1989 merger with Touche Ross in the US to create Deloitte & Touche, and a 1993 renaming to Deloitte Touche Tohmatsu. In 2002, it absorbed parts of Arthur Andersen’s UK, European, and American practices, and in 2013 it acquired Monitor Group, a major strategy consulting firm. Deloitte has sponsored events such as the 2012 Summer Olympics. It suffered a significant cyberattack in 2017 that compromised client confidentiality and employee data, and has faced litigation concerning several of its audits. By 2023, it was the fourth-largest privately owned organization in the United States and has consistently appeared on Fortune’s list of the 100 Best Companies to Work For.
Reader's Guide
Deloitte is a multinational professional services network headquartered in London, England, and is the largest such network globally by both revenue and headcount. It is one of the Big Four accounting firms, alongside EY, KPMG, and PwC. The network is composed of member firms of Deloitte Touche Tohmatsu Limited, a private company limited by guarantee incorporated in England and Wales. Founded in London in 1845 by accountant William Welch Deloitte, the firm expanded to the United States in 1890. Its growth included a 1952 merger with Haskins & Sells to form Deloitte Haskins & Sells, and a 1989 merger with Touche Ross in the US to create Deloitte & Touche. The international entity was renamed Deloitte Touche Tohmatsu in 1993, later shortened to Deloitte. In 2002, Deloitte absorbed parts of Arthur Andersen’s practices in the UK, Europe, and the Americas, and acquired the strategy consulting firm Monitor Group in 2013. The firm provides audit, consulting, financial advisory, risk, tax, and legal services, employing approximately 470,000 people across over 150 countries. In fiscal year 2024, its aggregate revenues reached US$67.2 billion. Deloitte sponsored the 2012 Summer Olympics. A major cyberattack in 2017 compromised client confidentiality and exposed employee information, and the firm has faced litigation over several audits. In 2023, it was the fourth-largest privately owned organization in the United States and has consistently appeared on Fortune’s list of the 100 Best Companies to Work For.
Position in the Investment Banking Hierarchy
The investment banking world is stratified into distinct tiers, and Deloitte Corporate Finance occupies a specific niche within that structure. Rather than being classified among the bulge bracket full-service banks that underwrite the majority of global financial transactions, or among the middle market banks pursuing smaller deals with comparable profitability, Deloitte appears in a separate category of notable advisory and capital markets firms. This placement signals a firm that brings specialized advisory capabilities to the capital markets space without operating as a full-service investment bank providing sales, market making, and research across equities, credit, rates, currency, commodities, and their derivatives. The distinction matters because it positions Deloitte Corporate Finance as a boutique or specialized player whose notability comes from advisory expertise rather than from the breadth of a universal banking franchise. In an industry where the largest firms by fees dominate headline rankings, Deloitte's presence in this separate listing underscores a different model of participation in capital markets—one rooted in targeted advisory work rather than the full spectrum of underwriting and trading activities that define the upper tier.
The Corporate Finance Designation
Deloitte's entry in the investment banking landscape is specifically identified as Deloitte Corporate Finance, a designation that signals a focused division rather than the entire organization operating as a standalone investment bank. This naming convention places it in the same category as Ernst & Young Capital Advisors, KPMG Corporate Finance, PwC Corporate Finance, and BDO Capital Advisors—each representing the capital markets arm of a larger professional services firm. The corporate finance label implies a concentration on advisory and transactional work within the broader capital markets ecosystem, as opposed to the full-service model where a single institution handles everything from sales and market making to research across a wide array of financial products including equities, credit, rates, currency, commodities, and their derivatives. By operating under a corporate finance banner, Deloitte participates in the advisory and capital markets segment of the industry without necessarily competing head-to-head with the bulge bracket institutions that underwrite the majority of the world's financial transactions. This structural choice reflects a specialization that aligns with the boutique and independent end of the market spectrum.
Among the Professional Services Cohort
Deloitte Corporate Finance shares a distinctive grouping with several other firms that trace their capital markets activities back to professional services origins rather than traditional banking. In the notable advisory and capital markets category, it sits alongside Ernst & Young Capital Advisors, KPMG Corporate Finance, PwC Corporate Finance, and BDO Capital Advisors. This clustering is not accidental; it reflects a pattern where large professional services organizations extend their advisory capabilities into the capital markets space through dedicated corporate finance divisions. These firms are distinguished from the full-service global investment banks that provide both advisory and financing services, sales, market making, and research on a broad array of financial products. They are also separate from the financial conglomerates that combine commercial banking, investment banking, and sometimes insurance—a combination that was common in Europe but restricted in the United States until the Gramm-Leach-Bliley Act of 1999. Deloitte's position in this cohort highlights a pathway into capital markets that leverages deep advisory expertise without requiring the full infrastructure of a universal bank.
Notability in a Tiered Industry
The investment banking industry is organized into a clear hierarchy, and Deloitte Corporate Finance's placement within it tells a specific story about its role. At the top sit the bulge bracket banks—those largest full-service institutions that underwrite the majority of financial transactions worldwide. Below them are middle market investment banks, sometimes called boutique or independent firms, which seek more deal flow with smaller-sized transactions while maintaining comparable profitability. Deloitte Corporate Finance is listed in yet another category: other notable advisory and capital markets firms that have achieved a degree of recognition. This is a category that also includes firms like Duff & Phelps, Roth MKM, Capital One Securities, and RBC Brewin Dolphin. The fact that Deloitte appears here rather than in the bulge bracket or middle market listings indicates that its notability in the investment banking world derives from its advisory and capital markets work as a specialized division. It is recognized for its contribution to the broader ecosystem of fundraising, advisory, and capital markets activity without being a primary underwriter or market maker in the way the upper-tier banks are.
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Frequently Asked Questions
Who is Deloitte?
Deloitte is a global professional services network headquartered in London, England, and is widely recognized as one of the four largest accounting and advisory firms on the planet. It sits in the group commonly called the Big Four, alongside EY, KPMG, and PwC.
What does Deloitte actually do?
The network delivers audit, tax, consulting, and advisory services to clients across virtually every industry and country. Measured by both revenue and total headcount, it is the largest professional services network in the world.
How is Deloitte structured legally?
Rather than being a single corporation, the network is made up of independent member firms that all operate under the umbrella of Deloitte Touche Tohmatsu Limited, a private company limited by guarantee incorporated in England and Wales. Each local office is its own legal entity.
Why is Deloitte significant in the business world?
As the largest professional services network by revenue and employee count, it shapes how audit, tax, and consulting work is delivered on a global scale. Its Big Four status means it handles a substantial share of corporate compliance and strategic advisory work across the world.
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