# 30 leading professional services firms in Chicago

Tamtam tracks 196 professional services firms headquartered in Chicago. This list ranks the 30 largest by number of employees on LinkedIn, led by JLL, Cushman & Wakefield and RSM US LLP. Their median headcount is 6,217. Half of them were founded in 1953 or later.

These Chicago-based professional services firms are predominantly large companies, many with a global presence. They offer a diverse range of expertise, from real estate and accounting to IT consulting and legal services. Notable companies include JLL, a real estate and investment management specialist, and RSM US LLP, which provides assurance, tax, and consulting services. Also present are Thoughtworks, a global technology consultancy, and Baker McKenzie, a law practice offering practical legal advice.

A significant concentration of these firms operates in the accounting and business consulting sectors, indicating a strong professional services hub in Chicago. Several of these large organizations, such as Cushman & Wakefield and Crowe, were founded in the early to mid-20th century, highlighting a long-standing tradition of professional services in the city.

🇺🇸 Chicago · 30 companies · Updated Nov 11, 2026

| # | Company | Industry | Headquarters | Employees | Founded |
|---|---|---|---|---|---|
| 1 | [JLL](https://www.tamtam.ai/c/jll) (jill.com)<br>A leading professional services firm specializing in real estate and investment management, creating rewarding opportunities and sustainable solutions using advanced technology | Real Estate | 🇺🇸 Chicago | 104,899 |  |
| 2 | [Cushman & Wakefield](https://www.tamtam.ai/c/cushman-and-wakefield) (cushmanwakefield.com)<br>Global commercial real estate services provider with 52,000 professionals focused on advancing client, colleague, and community outcomes worldwide. | Real Estate | 🇺🇸 Chicago | 53,000 | 1917 |
| 3 | [RSM US LLP](https://www.tamtam.ai/c/rsm-us-llp) (rsmus.com)<br>Provider of assurance, tax, and consulting services focused on middle market clients with a global presence and professional development culture. | Accounting | 🇺🇸 Chicago | 19,700 | 1926 |
| 4 | [HUB International](https://www.tamtam.ai/c/hub-international) (hubinternational.com)<br>Advises businesses and individuals on insurance, risk management, employee benefits, retirement, and wealth management with tailored solutions. | Insurance | 🇺🇸 Chicago | 16,129 |  |
| 5 | [Thoughtworks](https://www.tamtam.ai/c/thoughtworks) (thoughtworks.com)<br>A global technology consultancy specializing in strategy, design, and engineering to drive digital innovation, fostering diverse talent and a strong cultivation culture | IT Services and IT Consulting | 🇺🇸 Chicago | 12,735 |  |
| 6 | [Baker McKenzie](https://www.tamtam.ai/c/baker-mckenzie) (bakermckenzie.com)<br>Provide practical legal advice combining local knowledge and international expertise to help businesses succeed across global markets. | Law Practice | 🇺🇸 Chicago | 11,895 |  |
| 7 | [Grant Thornton (US)](https://www.tamtam.ai/c/grant-thornton-us) (grantthornton.com)<br>Provides independent audit, tax, and advisory services through a global network, focusing on quality, trust, and strong client relationships. | Professional Services | 🇺🇸 Chicago | 11,518 | 1924 |
| 8 | [BDO USA](https://www.tamtam.ai/c/bdo-usa) (bdo.com)<br>Providing middle market leaders with assurance, tax, and advisory services focused on cultivating a people-centered, growth-oriented corporate culture. | Accounting | 🇺🇸 Chicago | 11,182 | 1910 |
| 9 | [Baker Tilly US](https://www.tamtam.ai/c/baker-tilly-us) (bakertilly.com)<br>A leading advisory CPA firm with a coast-to-coast and global presence, part of Baker Tilly International network with 43,000 professionals | Accounting | 🇺🇸 Chicago | 10,594 |  |
| 10 | [Crowe](https://www.tamtam.ai/c/crowe-chicago) (crowe.com)<br>A global firm providing public accounting, consulting, and technology services, helping clients make smart decisions and uncover hidden opportunities worldwide | Professional Services | 🇺🇸 Chicago | 9,411 |  |
| 11 | [Kirkland & Ellis](https://www.tamtam.ai/c/kirkland-and-ellis) (kirkland.com)<br>Providing top-tier legal services in corporate transactions, litigation, investigations, and asset management with global reach and innovative approach. | Law Practice | 🇺🇸 Chicago | 8,683 | 1909 |
| 12 | [Kearney](https://www.tamtam.ai/c/kearney) (kearney.com)<br>Global consulting firm with a focus on people, strategic operations, and building the future through teamwork and hands-on expertise in over 40 countries | Business Consulting and Services | 🇺🇸 Chicago | 7,559 | 1926 |
| 13 | [Leo Burnett](https://www.tamtam.ai/c/leo-burnett) (leoburnett.com)<br>Global communications agency combining creativity, data, and technology to influence human behavior and drive client prosperity worldwide. | Advertising Services | 🇺🇸 Chicago | 6,825 |  |
| 14 | [Huron](https://www.tamtam.ai/c/huron) (huronconsultinggroup.com)<br>A global professional services firm specializing in strategy creation, operations optimization, digital transformation, and empowering businesses for sustainable results | Business Consulting and Services | 🇺🇸 Chicago | 6,453 | 2002 |
| 15 | [Accenture Strategy & Consulting](https://www.tamtam.ai/c/accenture-strategy-and-consulting) (accenture.com)<br>Combines deep industry expertise with advanced analytics and human-led design methodologies to help global clients act with speed and confidence throughout operations. | Business Consulting and Services | 🇺🇸 Chicago | 6,217 |  |
| 16 | [Sidley Austin LLP](https://www.tamtam.ai/c/sidley-austin-llp) (sidley.com)<br>Providing comprehensive legal services worldwide, specializing in complex transactions, restructuring, investigations, regulatory, and litigation matters across multiple industries. | Law Practice | 🇺🇸 Chicago | 5,113 | 1866 |
| 17 | [Mayer Brown](https://www.tamtam.ai/c/mayer-brown) (mayerbrown.com)<br>Representation of major corporations, funds, and financial institutions in complex transactions and disputes across international markets. | Law Practice | 🇺🇸 Chicago | 4,544 |  |
| 18 | [Sargent & Lundy](https://www.tamtam.ai/c/sargent-and-lundy) (sargentlundy.com)<br>A global leader in architect engineering specializing in power, energy, and decarbonization, offering comprehensive project services to public and private clients | Professional Services | 🇺🇸 Chicago | 4,511 | 1891 |
| 19 | [AHEAD](https://www.tamtam.ai/c/ahead-chicago) (ahead.com)<br>This company specializes in building and managing digital platforms for successful organizations, accelerating the impact of technology through innovative solutions and engineering expertise | IT Services and IT Consulting | 🇺🇸 Chicago | 4,223 |  |
| 20 | [Spencer Stuart](https://www.tamtam.ai/c/spencer-stuart) (spencerstuart.com)<br>Specializes in senior executive search, board recruitment, leadership advisory, succession planning, and organizational effectiveness for diverse global clients. | Business Consulting and Services | 🇺🇸 Chicago | 3,609 |  |
| 21 | [Chartis](https://www.tamtam.ai/c/chartis) (chartis.com)<br>Consulting firm specializing in healthcare strategy, transformation, and operational models to improve affordability, accessibility, safety, and patient experience. | Business Consulting and Services | 🇺🇸 Chicago | 3,598 | 2001 |
| 22 | [Cushman & Wakefield - Formerly DTZ](https://www.tamtam.ai/c/cushman-and-wakefield-formerly-dtz) (cushmanwakefield.com)<br>A global leader in commercial real estate services, providing insights and value for occupiers and investors worldwide through various core services | Commercial Real Estate | 🇺🇸 Chicago | 3,518 |  |
| 23 | [Perkins&Will](https://www.tamtam.ai/c/perkins-and-will) (perkinswill.com)<br>Design and architecture firm creating healthy, beautiful spaces worldwide with expertise in architecture, interior design, urban and landscape planning. | Architecture and Planning | 🇺🇸 Chicago | 3,060 | 1935 |
| 24 | [Staff Management \| SMX](https://www.tamtam.ai/c/staff-management-smx) (staffmanagement.com)<br>A leader in workforce solutions for fulfillment, distribution, and manufacturing industries, specializing in Onsite Workforce Management and Recruitment and Placement Solutions | Staffing and Recruiting | 🇺🇸 Chicago | 3,025 | 1988 |
| 25 | [Intellias](https://www.tamtam.ai/c/intellias) (intellias.com)<br>Trusted technology partner accelerating sustainable digitalization for top-tier organizations, delivering mission-critical projects and measurable outcomes for clients globally | IT Services and IT Consulting | 🇺🇸 Chicago | 2,955 | 2002 |
| 26 | [Credico](https://www.tamtam.ai/c/credico) (credico.com)<br>A leading customer acquisition agency connecting brands with local sales teams to acquire new customers through face-to-face methods | Advertising Services | 🇺🇸 Chicago | 2,779 | 1991 |
| 27 | [Clayco](https://www.tamtam.ai/c/clayco) (claycorp.com)<br>A full-service real estate development, architecture, engineering, and construction firm delivering high-quality solutions within North America on time and on budget | Construction | 🇺🇸 Chicago | 2,744 | 1984 |
| 28 | [Heidrick & Struggles](https://www.tamtam.ai/c/heidrick-and-struggles) (heidrick.com)<br>Providing executive search, leadership consulting, and corporate culture services to global Fortune 1000 companies for improved performance. | Business Consulting and Services | 🇺🇸 Chicago | 2,477 | 1953 |
| 29 | [West Monroe](https://www.tamtam.ai/c/west-monroe) (westmonroe.com)<br>Global consulting firm specializing in business and technology solutions, focusing on rapid impact through industry, strategy, and people integration. | Business Consulting and Services | 🇺🇸 Chicago | 2,416 | 2002 |
| 30 | [Sikich](https://www.tamtam.ai/c/sikich) (sikich.com)<br>A global professional services company specializing in technology solutions, delivering transformative digital strategies and financial services to various clients worldwide | Business Consulting and Services | 🇺🇸 Chicago | 2,335 | 1982 |

## How this list is built

Every company on this list has a Tamtam company profile. The industry is the one the company gives on LinkedIn; categories such as SaaS or fintech are classified by Tamtam's AI from the company's website and LinkedIn page; and the headquarters city must match the company's own address. Companies are ranked by the number of employees on LinkedIn, and the list is refreshed every night. Classifications can be wrong, so treat the list as a starting point rather than an official ranking. Last updated Nov 11, 2026.

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Source: https://www.tamtam.ai/l/professional-services-firms-chicago