Consulting firms in Illinois

Accenture plc is a global management consulting, technology services and outsourcing company headquartered in Dublin, Republic of Ireland. It is the largest consulting firm in the world and is a Fortune Global 500 company. As of August 2015, the company had more than 373,000 employees across 130 countries. Accenture's current clients include 96 of the Fortune Global 100 and more than three-quarters of the Fortune Global 500. Previously incorporated in the USA, then in Bermuda, since September 1, 2009 the company has been incorporated in Ireland.

Aerial Metrics works to enable public safety agencies and private crash reconstructionists to take advantage of smalled unmanned aerial systems (sUAS) and aerial photogrammtery to perform forensic mapping of crash and crime scenes.

Alvarez & Marsal (A&M), is an independent global professional services firm, with expertize in operational and turnaround management. It helps companies improve operating and financial performance, and navigate business, litigation and tax matters.

Aon Corporation is an American public multinational corporation headquartered in Chicago, Illinois, USA that provides risk management services, insurance and reinsurance brokerage, human capital and management consulting, and specialty insurance underwriting. Aon has approximately 500 offices worldwide, serving 120 countries with 59,000 employees.

Archstone Consulting, a division of The Hackett Group, Inc., is a strategy and operations advisory firm with deep expertise in the consumer packaged goods, life sciences and manufacturing industries.

Avanade Inc. was founded in 2000 as a joint venture between Accenture and Microsoft to serve an untapped market for Microsoft-focused consulting services. The company provides IT services focused on the Microsoft platform for mid-sized to large enterprise organizations. Headquartered in Seattle, Washington, the company has 70+ locations worldwide and employs more than 19,600 professionals. Today, Avanade is majority-owned by Accenture.

Bain & Company is a global management consulting firm headquartered in Boston, Massachusetts. It provides advisory services to businesses, nonprofit organizations, and governments, and is one of the Big Three management consulting firms. The CEO is Bob Bechek and the CFO is Len Banos. Bain has 53 offices in 34 countries and 5,700 employees.

BDO International is a worldwide professional services network of public accountancy firms, serving national and international clients. Each BDO Member Firm is an independent legal entity in its own country. The network, originally formed in 1963 as Binder Seidman International Group, is coordinated by BDO Global Coordination B.V., with an office in Brussels, Belgium. The name BDO, first devised in 1973, is an acronym of Binder Dijker Otte & Co.

Booz Allen Hamilton Inc. NYSE: BAH, or more commonly Booz Allen, is an American public consulting firm headquartered in McLean, Fairfax County, Virginia, with 80 other offices throughout the United States. Ralph Shrader is its Chairman and Chief Executive Officer. The firm was founded by Edwin Booz in Chicago circa 1914. It is listed as number 438 in the 2011 Fortune 500.

Bridge Strategy Group is a general management consultancy and a part of the Mahindra Satyam family of companies.

Buck Consultants is a global HR benefits and human resource consulting firm.

Campbell Alliance is a specialized management consulting firm that serves the pharmaceutical and biotechnology industry. The firm is privately owned and was founded in 1997 by a former executive of GlaxoWellcome.