Grant Thornton LLP

Grant Thornton LLP is a major U.S. accounting and professional-services firm serving public companies, privately held businesses, government organizations, and nonprofit institutions. Its principal service lines are audit and assurance, tax, and advisory. Advisory work spans areas such as transactions, restructuring, cybersecurity, technology modernization, risk, internal controls, disputes, investigations, and business consulting. The firm operates under the Grant Thornton name but is legally distinct from Grant Thornton International Ltd and from the independent member firms that make up the wider Grant Thornton network. Grant Thornton International coordinates the global brand, methodologies, and cross-border capabilities; it does not generally operate as a single worldwide accounting partnership in the same way as a centralized multinational corporation. This structure allows the U.S. firm to serve domestic clients while collaborating with member firms in other jurisdictions. The U.S. practice traces its history to the Alexander Grant accounting business established in Chicago in the 1920s. It later developed through expansion, acquisitions, and combinations with other accounting practices, including the firm associated with Thornton Baker. The Grant Thornton name became associated with a broader international network during the late twentieth century. In the United States, the firm grew beyond traditional audit and tax work by building consulting and transaction-advisory capabilities and by focusing on middle-market companies as well as larger and more complex organizations. Grant Thornton differentiates itself through a combination of accounting-firm credentials, sector specialization, and advisory services. Its clients include organizations in financial services, manufacturing, consumer and industrial markets, healthcare, public sector, technology, media, telecommunications, and private equity. The firm also publishes research and practical guidance on accounting standards, tax policy, governance, risk, technology, and business transformation. As a professional-services partnership, Grant Thornton LLP is not a publicly traded company and does not have a stock ticker. Publicly available information about the U.S. practice is commonly reported through firm announcements, professional directories, regulatory records, and Grant Thornton International materials rather than through public-company filings. The firm remains an active participant in the U.S. accounting and consulting market and is one of the largest accounting organizations operating under a non-Big Four global brand.

Grant Thornton LLP is part of the Grant Thornton family of accounting and advisory firms. The U.S. practice traces its roots to the Alexander Grant accounting firm, established in Chicago in 1924. Alexander Grant & Co. developed as an independent accounting practice serving American businesses and gradually expanded its geographic reach and professional capabilities. Its early business was centered on audit and accounting, with tax work becoming an increasingly important part of the service offering as the regulatory and corporate environment developed. The Grant Thornton identity reflects the later combination of the Alexander Grant organization with the Thornton Baker firm. Thornton Baker originated in the United Kingdom and had an international orientation. The combination helped create the basis for the Grant Thornton name and for a network capable of serving clients with operations in more than one country. Over time, the international organization developed as a network of legally separate member firms. The U.S. firm remained a separate professional-services entity while participating in common branding, methodologies, and cross-border client service through Grant Thornton International. During the late twentieth and early twenty-first centuries, Grant Thornton LLP broadened its market position beyond conventional accounting. Audit and tax remained foundational, but the firm invested in advisory capabilities covering transactions, performance improvement, risk management, information technology, cybersecurity, disputes, investigations, and restructuring. These capabilities enabled it to compete for work from private-equity sponsors, fast-growing companies, public-sector bodies, and larger corporations as well as its traditional base of privately owned and middle-market businesses. The firm’s development also reflects wider changes in the accounting profession. Clients increasingly sought integrated help with compliance, governance, enterprise risk, data, digital systems, operational change, and major transactions. Grant Thornton responded by organizing specialists around industries and business problems rather than limiting the brand to statutory audit. Its industry coverage has included financial services, healthcare, manufacturing, consumer and industrial markets, technology, media and telecommunications, public sector, and not-for-profit organizations. Grant Thornton LLP operates as a private professional-services firm rather than a listed corporation. Its legal and organizational relationship with Grant Thornton International is important: the global network provides an international platform, but member firms are independently owned and managed in their respective jurisdictions. Consequently, the U.S. firm’s financial results, governance, and regulatory responsibilities are distinct from those of other Grant Thornton firms. In the 2020s, Grant Thornton continued to present itself as a multidisciplinary accounting and advisory organization, with particular emphasis on technology-enabled transformation, tax complexity, transaction support, cyber and digital risk, and audit quality. Leadership passed from Brad Preber to Seth Siegel in 2024. The firm remains active in the U.S. market and retains a position among the largest accounting organizations outside the Big Four.

• 2024

  Seth Siegel became U.S. chief executive

  [3]Seth Siegel named CEO of Grant Thornton LLPgrantthornton.com

  Seth Siegel succeeded Brad Preber as chief executive officer of Grant Thornton LLP.

• 2018

  Brad Preber became U.S. chief executive

  [3]Seth Siegel named CEO of Grant Thornton LLPgrantthornton.com

  Brad Preber began serving as chief executive officer of Grant Thornton LLP.

• 1986

  Grant Thornton name adopted in the United States

  [2]About Grant Thorntongrantthornton.com

  The U.S. organization became associated with the Grant Thornton name following the development of the international accounting-firm combination and network.

• 1924

  Alexander Grant accounting firm established

  [2]About Grant Thorntongrantthornton.com

  The U.S. predecessor associated with Alexander Grant was established in Chicago, forming the historical foundation of the modern U.S. Grant Thornton practice.

A full-service U.S. accounting and advisory firm positioned around audit quality, sector expertise, and practical support for middle-market and large organizations.

• Professional services

  Audit and assurance

  Grant Thornton provides financial statement audits, reviews, attest services, and related assurance work. The practice also addresses accounting standards, internal controls, public-company reporting, governance, and reporting issues faced by private and public organizations.

• Professional services

  Tax

  Tax services include compliance, planning, controversy support, international and state-and-local tax, transaction tax, and tax advice connected with business restructuring and investment. The offering serves corporations, partnerships, private businesses, executives, and tax-exempt organizations.

• Professional services

  Advisory

  The advisory practice helps clients with transactions, strategy, operational improvement, finance transformation, technology implementation, risk, cybersecurity, data, and enterprise change. It combines accounting knowledge with consulting and specialist capabilities.

• Advisory services

  Restructuring and turnaround

  Restructuring professionals advise companies, lenders, investors, and other stakeholders on liquidity, operational performance, distressed situations, bankruptcy-related matters, and turnaround planning.

• Advisory services

  Forensic, investigative, and dispute services

  These services support investigations, fraud and misconduct reviews, litigation, damages analysis, expert testimony, and disputes involving financial, accounting, and operational evidence.

• 2024

  U.S. leadership transitionStrategy

  Background

  Grant Thornton was continuing to develop its audit, tax, and advisory platform as client demand expanded toward technology, transformation, transactions, and risk services.

  Action taken

  The firm appointed Seth Siegel as chief executive officer, succeeding Brad Preber.

  Aftermath

  Siegel became the U.S. firm’s chief executive and continued the organization’s focus on multidisciplinary professional services.

  Source

1. 1Grant Thornton United Statesgrantthornton.com
2. 2About Grant Thorntongrantthornton.com
3. 3Seth Siegel named CEO of Grant Thornton LLPgrantthornton.com
4. 4Grant Thornton International networkgrantthornton.global