Sidley Austin
An American multinational law firm headquartered in Chicago.
Last updated October 14, 2026
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Overview
Sidley Austin LLP is an American multinational law firm headquartered at One South Dearborn in Chicago's Loop. Established in 1866 as Williams & Thompson by Norman Williams and John L. Thompson, it developed from a Chicago practice serving industrial, communications, transportation, financial and public-sector clients into a global firm with approximately 2,300 lawyers in 21 offices across North America, Europe, Asia and Australia. Its work spans corporate and transactional law, litigation, appellate and Supreme Court advocacy, securities, structured finance, capital markets, international trade, competition, regulatory matters, healthcare, life sciences, real estate, intellectual property, tax, employment and investigations. The firm's early history is closely linked to Chicago's industrial and communications economy. It helped organize Western Electric and Illinois Bell in the nineteenth century, and the Bell System became a long-standing client. Other early clients included the Pullman Company and Illinois Steel. William Pratt Sidley joined the practice in 1892 and was added to the firm name in 1900. Edwin C. Austin joined in 1914, contributing to the name that later became associated with Sidley & Austin. Sidley expanded beyond Chicago during the twentieth century. It established a Washington, D.C. office in 1963 under former U.S. Postmaster General J. Edward Day, merged with Leibman, Williams, Bennett, Baird & Minow in 1972, and opened offices in London in 1974 and Singapore and New York in 1982. The firm represented AT&T in the period surrounding the United States' antitrust case against the telecommunications company. In 1985, it created one of the first standalone law-firm practices devoted to appeals before the U.S. Supreme Court, recruiting Benjamin W. Heineman Jr. and former Solicitor General Rex E. Lee. Carter Phillips later became one of the firm's most prominent Supreme Court advocates. The 2001 combination with Brown & Wood materially broadened Sidley's securities, structured-finance, securitization and New York capabilities. Brown & Wood had offices in the World Trade Center, and the combined firm's planned expansion there was disrupted by the September 11 attacks; Sidley subsequently moved its New York office to the Axa Equitable Center. The firm also developed an international trade practice in 2002 and established its Chicago headquarters at One South Dearborn in 2003. Sidley is known for high-end litigation, appellate advocacy, cross-border transactions and regulatory work. Its international trade lawyers have represented parties in a substantial share of World Trade Organization disputes, including Airbus in proceedings concerning European Union countermeasures related to Boeing subsidies. The firm also advises multinational companies on sanctions, export controls, trade policy, foreign investment, national security and government investigations. Its public profile has been shaped both by legal achievements and by prominent former lawyers. Barack Obama and Michelle Obama worked at the Chicago office at the beginning of their legal careers, and other alumni include Rex E. Lee, George Deukmejian, Newton Minow, David S. Tatel and J. Edward Day. The firm has also undertaken substantial pro bono work, including George Fatheree's representation of the descendants of Willa and Charles Bruce in the restoration of Bruce's Beach property in California in 2022. Sidley remains an active global firm. It added Miami in 2022 and San Diego in 2024. Publicly reported matters in recent years have included representation and lobbying work for Chinese technology companies, including Huawei, Hikvision USA and DJI Technologies. These engagements have attracted scrutiny because of the clients' connections to U.S. national-security, sanctions and export-control debates. The firm has also received recognition for client service, international trade, capital markets, compliance, healthcare, life sciences, real estate and appellate work.
History
Sidley Austin traces its origins to 1866, when Norman Williams and John L. Thompson established Williams & Thompson in Chicago. The young firm advised businesses during the city's industrial growth and became involved in significant corporate work. In 1876 it helped organize Western Electric and Illinois Bell, while the Bell System later developed into a major long-term client. Mary Todd Lincoln was also an early client, seeking legal advice after President Abraham Lincoln's death. The firm's early business included work for the Pullman Company, Western Electric and Illinois Steel. William Pratt Sidley joined the firm in 1892, and his name entered the partnership title in 1900. Edwin C. Austin joined in 1914. Through successive name changes and combinations, the practice evolved into Sidley & Austin and built a reputation in corporate, communications, transportation, financial and public-sector matters. The firm began a more deliberate national and international expansion in the second half of the twentieth century. Former U.S. Postmaster General J. Edward Day established the Washington, D.C. office in 1963. In 1972, Sidley & Austin combined with the 50-lawyer Chicago firm Leibman, Williams, Bennett, Baird & Minow, then opened in London in 1974 and in Singapore and New York in 1982. A dispute involving Day over the relocation and governance of the Washington office was rejected by the federal courts and later became a reference point in discussions of partnership law. During this period Sidley handled prominent litigation and regulatory matters. Charles E. Lomax joined in 1975 and later became the firm's first Black partner. He represented clients including boxing promoter Don King and Muhammad Ali. The firm represented AT&T during the period surrounding the federal government's antitrust case against the telecommunications company. In 1985 Sidley established a dedicated appellate practice focused on U.S. Supreme Court litigation, recruiting Benjamin W. Heineman Jr. and former Solicitor General Rex E. Lee. The practice later became one of the firm's signature capabilities, with Carter Phillips among its leading advocates. Sidley was involved in the Savings and Loan Crisis as counsel to Lincoln Savings and Loan Association. In 1991 it paid $7.5 million to settle legal-malpractice claims related to that representation. In 1995, women lawyers at the firm co-founded its Women in Leadership program. The Chicago office also became notable for the early careers of Barack Obama and Michelle Obama, who met while working there in 1989. A defining corporate milestone came in 2001, when Sidley & Austin merged with Brown & Wood, a New York firm founded in 1914. Brown & Wood brought major securities, structured-finance and securitization practices, as well as offices in New York, Washington, San Francisco, Los Angeles, London, Beijing and Hong Kong. The planned move into expanded World Trade Center space was interrupted by the September 11 attacks; the New York practice moved to the Axa Equitable Center in 2002. In 2002 the firm created a dedicated international trade practice, and in 2003 it became the anchor tenant of One South Dearborn in Chicago. The firm's tax-shelter work generated major controversy in the 2000s. Sidley and KPMG agreed in 2006 to pay $54 million to investors connected with the shelters, and Sidley agreed in 2007 to pay $39 million to the IRS in a settlement that avoided criminal charges concerning alleged fraudulent tax-shelter activity. In the following decades Sidley further developed its cross-border and regulatory platform. Its lawyers represented parties in numerous WTO disputes, including Airbus in the dispute over Boeing subsidies. The firm has advised clients on international trade, sanctions, export controls, national security, foreign-agent registration and government investigations. Its representation of Huawei, Hikvision USA and DJI Technologies drew public attention because of the U.S. government's scrutiny of Chinese technology companies. The firm has continued expanding its office network, adding Miami in 2022 and San Diego in 2024. It has also maintained a substantial pro bono practice. Partner George Fatheree worked for more than 1,000 hours on the effort to return Bruce's Beach to the descendants of Willa and Charles Bruce; the property was restored to their great-grandsons in July 2022. Sidley's later recognition has included repeated honors for client service, international trade, capital markets, compliance, healthcare, life sciences, real estate and appellate advocacy.
- 2024
San Diego office added
[1]Sidley adds San Diego to its global office network.
- 2022
Miami office opens
[1]The firm expands its U.S. office network with a Miami location.
- 2003
One South Dearborn becomes Chicago headquarters
[1]Sidley becomes the anchor tenant of One South Dearborn in downtown Chicago.
- 2002
International trade practice launches
[1]The firm becomes one of the early large law firms to establish a practice dedicated to international trade law.
- 2001
Brown & Wood merger
[1]The merger adds major securities, structured-finance, securitization and international capabilities.
- 1985
Dedicated Supreme Court practice is established
[1]Sidley creates a standalone appellate practice focused on U.S. Supreme Court cases.
- 1972
Merger with Leibman Williams
[1]Sidley & Austin combines with the Chicago firm Leibman, Williams, Bennett, Baird & Minow.
- 1963
Washington, D.C. office opens
[1]Former Postmaster General J. Edward Day establishes the firm's Washington office.
- 1900
Sidley name enters the firm title
[1]William Pratt Sidley's name is added after he joins the practice in the 1890s.
- 1876
Early communications-sector work
[1]The firm helps organize Western Electric and Illinois Bell, beginning a long association with the Bell System.
Products and positioning
A premium full-service international law firm with particularly strong practices in complex litigation, appellate advocacy, securities and structured finance, international trade, corporate transactions and highly regulated industries.
Legal services
Corporate and transactional services
Sidley advises companies, financial institutions and investors on mergers and acquisitions, joint ventures, governance, private equity, public offerings, capital markets and cross-border transactions. The practice is designed for complex matters involving multiple jurisdictions, regulated industries and significant financing or disclosure requirements.
Legal services
Litigation and dispute resolution
The firm represents corporations and institutions in commercial disputes, securities cases, investigations, class actions, product matters and high-stakes regulatory litigation. Its lawyers handle proceedings in U.S. courts, international tribunals and other adjudicative forums.
Legal services · 1985
Appellate and Supreme Court advocacy
Sidley's dedicated appellate practice advises clients on appeals and constitutional, administrative and statutory questions, with a particular emphasis on the U.S. Supreme Court. The practice was established in 1985 and became a prominent part of the firm's litigation identity.
Legal services · 2002
International trade and customs
Sidley counsels clients on tariffs, export controls, sanctions, customs, trade remedies, national-security reviews and WTO disputes. The practice serves companies and governments involved in cross-border commerce and trade-policy conflicts.
Legal services · 2001
Securities and structured finance
The firm advises issuers, financial institutions and investors on securities offerings, securitizations, structured products and related regulatory matters. These capabilities were strengthened by the 2001 combination with Brown & Wood.
Controversies
2022
Hikvision foreign-agent registration scrutiny
Sidley's updated registration for work for Hikvision USA attracted attention because of the client's connection to a Chinese surveillance-technology company and U.S. national-security concerns.
2007
IRS tax-shelter settlement
The firm agreed to pay $39 million to the Internal Revenue Service concerning alleged fraudulent tax-shelter activities, resolving the matter without criminal charges.
2006
Tax-shelter investor settlement
Sidley and KPMG agreed to pay $54 million to investors who had purchased disputed tax shelters.
1991
Lincoln Savings and Loan malpractice settlement
Sidley paid $7.5 million to settle legal-malpractice claims arising from its representation of Lincoln Savings and Loan Association during the Savings and Loan Crisis.
Marketing campaigns
- 2022Bruce's Beach pro bono representation
United States
Sidley partner George Fatheree represented descendants of Willa and Charles Bruce in the effort to restore beachfront property seized by Los Angeles authorities in the 1920s. The matter involved more than 1,000 hours of pro bono work and concluded with the property being returned to the family's great-grandsons.
Outcome. Property was restored to the descendants on July 20, 2022.
- 1995Women in Leadership program
Global
Women lawyers at Sidley co-founded a program intended to support women's leadership and advancement within the legal profession and the firm.
Outcome. The initiative became part of the firm's diversity and professional-development history.
Brand decisions
2024
Open San Diego officeStrategyBackground
Sidley continued its expansion in important U.S. business and technology markets.
Action taken
The firm added San Diego to its global network.
Aftermath
San Diego became part of the firm's expanding U.S. office footprint.
2022
Open Miami officeStrategyBackground
The firm continued extending its U.S. geographic coverage.
Action taken
Sidley added Miami to its office network.
Aftermath
The expansion increased the firm's presence in a major U.S. commercial and Latin America-facing market.
2002
Establish a dedicated international trade practiceStrategyBackground
Globalization and expanding trade disputes created demand for specialized advice combining litigation, government relations and regulatory analysis.
Action taken
Sidley created a practice focused specifically on international trade law.
Aftermath
International trade became a major part of the firm's global offering, including representation in WTO disputes.
2001
Merge with Brown & WoodM&ABackground
Sidley sought to expand its New York, securities, structured-finance, securitization and international capabilities.
Action taken
The firm combined with Brown & Wood, adding lawyers and offices in the United States, Europe and Asia.
Aftermath
The combination substantially broadened Sidley's financial-services and cross-border platform.
1985
Create a standalone Supreme Court practiceStrategyBackground
The firm identified specialized appellate advocacy as a strategic area in which a large law firm could build a distinct national practice.
Action taken
Sidley recruited Benjamin W. Heineman Jr. and former Solicitor General Rex E. Lee to lead a dedicated U.S. Supreme Court practice.
Aftermath
The practice became one of Sidley's best-known capabilities and developed a substantial Supreme Court caseload.
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