Company lists · Data refreshed September 2026

Top 25 Big 5 law firms based in Chicago, United States

Name: Big 5 law firms based in Chicago, United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 23, 2026 492 companies tracked

RevenueBase identified 492 big 5 law firms headquartered in Chicago, United States as of September 2026 and tracks 49,440 professional contacts across them, including 28,869 with verified work emails. Across the United States, New York is the largest hub for this category (1,021 companies); Chicago follows with 492.

This list covers big 5 law firms headquartered in Chicago, United States, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 23, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 23, 2026 86% judged on-target in blind review

492Companies

49,440Contacts tracked

28,869Verified emails

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The 25 largest big 5 law firms based in Chicago, United States

Ranked by team size

Top 25 of 492 big 5 law firms based in Chicago, United States, ranked by team size, largest first. Data refreshed Sep 23, 2026. RevenueBase Smart Search rates how each company's information relates to big 5 law firms: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	Baker Mckenzie	Indirect evidence	Chicago, IL, United StatesHQ checked Sep 23, 2026	10001+	9,815 contacts →
	Indirect evidence “Baker McKenzie empowers clients to compete in the global economy.” Source: RevenueBase Database · checked Sep 23, 2026
2	Kirkland & Ellis	Partial evidence	Chicago, IL, United StatesHQ checked Sep 23, 2026	5,001-10,000	8,449 contacts →
	Partial evidence “As one of the world’s leading law firms, we serve a broad range of clients with market-leading practices in private equity, M&A and other complex corporate transactions…” Source: RevenueBase Database · checked Sep 23, 2026
3	Sidley Austin LLP	Partial evidence	Chicago, IL, United StatesHQ checked Sep 23, 2026	1,001-5,000	5,169 contacts →
	Partial evidence “Sidley is an elite global law firm.” Source: RevenueBase Database · checked Sep 23, 2026
4	Mayer Brown	Partial evidence	Chicago, IL, United StatesHQ checked Sep 23, 2026	1,001-5,000	4,177 contacts →
	Partial evidence “Mayer Brown is a leading international law firm, positioned to represent the world’s major corporations, funds and financial institutions in their most important and complex…” Source: RevenueBase Database · checked Sep 23, 2026
5	Winston & Strawn LLP	Indirect evidence	Chicago, IL, United StatesHQ checked Sep 23, 2026	1,001-5,000	2,215 contacts →
	Indirect evidence “On June 1, 2026, Winston & Strawn and Taylor Wessing’s U.K-led business officially launched as a single combined firm, creating Winston Taylor.” Source: RevenueBase Database · checked Sep 23, 2026
6	Seyfarth Shaw LLP	Indirect evidence	Chicago, IL, United StatesHQ checked Sep 23, 2026	1,001-5,000	2,167 contacts →
	Indirect evidence “High stakes.” Source: RevenueBase Database · checked Sep 23, 2026
7	Katten Muchin Rosenman LLP	Partial evidence	Chicago, IL, United StatesHQ checked Sep 23, 2026	1,001-5,000	1,495 contacts →
	Partial evidence “Katten is a full-service law firm with nearly 650 attorneys in locations across the United States and in London and Shanghai.” Source: RevenueBase Database · checked Sep 23, 2026
8	Jenner & Block	Indirect evidence	Chicago, IL, United StatesHQ checked Sep 23, 2026	501-1,000	1,194 contacts →
	Indirect evidence “At Jenner & Block, we shape what’s next through experience, vision, and judgment.” Source: RevenueBase Database · checked Sep 23, 2026
9	Hinshaw & Culbertson LLP	Partial evidence	Chicago, IL, United StatesHQ checked Sep 23, 2026	501-1,000	1,188 contacts →
	Partial evidence “Hinshaw & Culbertson LLP is a U.S-based law firm with offices nationwide.” Source: RevenueBase Database · checked Sep 23, 2026
10	Vedder	Indirect evidence	Chicago, IL, United StatesHQ checked Sep 23, 2026	501-1,000	866 contacts →
	Indirect evidence “With more than 400 lawyers and professionals across key global markets including Chicago, Dallas, Los Angeles, London, Miami, New York, San Francisco, Singapore, and Washington…” Source: RevenueBase Database · checked Sep 23, 2026
11	O'hagan Meyer	Partial evidence	Chicago, IL, United StatesHQ checked Sep 23, 2026	501-1,000	579 contacts →
	Partial evidence “As a national law firm defending corporations, non-profits, associations and their officers & directors in every manner of litigation, O'Hagan Meyer provides individualized…” Source: RevenueBase Database · checked Sep 23, 2026
12	Chapman And Cutler LLP	Partial evidence	Chicago, IL, United StatesHQ checked Sep 23, 2026	201-500	565 contacts →
	Partial evidence “Chapman is a law firm focused on finance.” Source: RevenueBase Database · checked Sep 23, 2026
13	Amundsen Davis, LLC	Partial evidence	Chicago, IL, United StatesHQ checked Sep 23, 2026	201-500	542 contacts →
	Partial evidence “Amundsen Davis is a law firm comprised of over 250 attorneys headquartered in Chicago.” Source: RevenueBase Database · checked Sep 23, 2026
14	Litchfield Cavo LLP	Indirect evidence	Chicago, IL, United StatesHQ checked Sep 23, 2026	501-1,000	424 contacts →
	Indirect evidence “Litchfield Cavo LLP began as a small firm of attorneys experienced in insurance and business defense matters.” Source: RevenueBase Database · checked Sep 23, 2026
15	Neal, Gerber & Eisenberg LLP	Partial evidence	Chicago, IL, United StatesHQ checked Sep 23, 2026	201-500	353 contacts →
	Partial evidence “Neal Gerber Eisenberg is a Chicago-based law firm whose attorneys share a culture of teamwork and devotion to personalized client service to advance our clients’ business…” Source: RevenueBase Database · checked Sep 23, 2026
16	Schiff Hardin LLP	Indirect evidence	Chicago, IL, United StatesHQ checked Sep 23, 2026	501-1,000	297 contacts →
	Indirect evidence “Schiff Hardin LLP is now ArentFox Schiff.” Source: RevenueBase Database · checked Sep 23, 2026
17	Banner Witcoff	Indirect evidence	Chicago, IL, United StatesHQ checked Sep 23, 2026	201-500	288 contacts →
	Indirect evidence “For more than 100 years Banner Witcoff has provided sound protection and inventive intellectual property solutions for some of the world’s most innovative organizations.” Source: RevenueBase Database · checked Sep 23, 2026
18	Levenfeld Pearlstein, LLC	Strong evidence	Chicago, IL, United StatesHQ checked Sep 23, 2026	51-200	254 contacts →
	Strong evidence “Formed in Levenfeld Pearlstein provides the sophisticated skills and resources of a big law firm with the personal attention of a small law firm.” Source: RevenueBase Database · checked Sep 23, 2026
19	Swanson, Martin & Bell, LLP	Indirect evidence	Chicago, IL, United StatesHQ checked Sep 23, 2026	201-500	254 contacts →
	Indirect evidence “Swanson, Martin & Bell, LLP was founded in 1992 by a group of trial lawyers who left a large Chicago firm to better serve the needs of their clients.” Source: RevenueBase Database · checked Sep 23, 2026
20	Barack Ferrazzano Kirschbaum & Nagelberg LLP	Indirect evidence	Chicago, IL, United StatesHQ checked Sep 23, 2026	201-500	250 contacts →
	Indirect evidence “Barack Ferrazzano was founded in 1984 with a vision focused on delivering efficient, team-oriented services of the highest quality.” Source: RevenueBase Database · checked Sep 23, 2026
21	Tressler LLP	Partial evidence	Chicago, IL, United StatesHQ checked Sep 23, 2026	51-200	237 contacts →
	Partial evidence “Tressler LLP is a national law firm headquartered in Chicago, with ten offices located in six states - California, Illinois, Missouri, New Jersey, New York and Pennsylvania.” Source: RevenueBase Database · checked Sep 23, 2026
22	Clausen Miller P.C	Indirect evidence	Chicago, IL, United StatesHQ checked Sep 23, 2026	201-500	232 contacts →
	Indirect evidence “Founded over 80 years ago, Clausen Miller represents businesses, insurers and professionals through strategic, cost-effective litigation and counseling across the nation and…” Source: RevenueBase Database · checked Sep 23, 2026
23	Marshall, Gerstein & Borun LLP	Partial evidence	Chicago, IL, United StatesHQ checked Sep 23, 2026	51-200	213 contacts →
	Partial evidence “Marshall, Gerstein & Borun LLP has one focus - intellectual property law.” Source: RevenueBase Database · checked Sep 23, 2026
24	Much Shelist, P.C	Indirect evidence	Chicago, IL, United StatesHQ checked Sep 23, 2026	51-200	203 contacts →
	Indirect evidence “We're Much.” Source: RevenueBase Database · checked Sep 23, 2026
25	Cassiday Schade LLP	Partial evidence	Chicago, IL, United StatesHQ checked Sep 23, 2026	51-200	186 contacts →
	Partial evidence “Cassiday Schade is a litigation law firm headquartered in Chicago, with national presence.” Source: RevenueBase Database · checked Sep 23, 2026

RevenueBase Smart Search

RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: big 5 law firms. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.

Strong evidence: The company's own public description of its business names big 5 law firms.
Partial evidence: Its own public description names part of big 5 law firms, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name big 5 law firms. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.

RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.

Showing 25 of 492 big 5 law firms based in Chicago, United States

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Big 5 law firms based in Chicago, United States at a glance

As of Sep 23, 2026

58.4%Verified-email coverage

100.5Average contacts per company

1-10Median size (employees)

Sep 23, 2026Page data refreshed

Companies by employee count

1-10

277

11-50

136

51-200

201-500

501-1,000

1,001-5,000

5,001-10,000

10001+

Email recency for this list is measured across the whole United States list rather than for Chicago, so it is reported there. Company counts and contact totals on this page are exact for Chicago, over 492 companies.

How this list was built

Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among big 5 law firms, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.

Source: The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
What qualifies: Companies headquartered in Chicago, United States whose own description of what they do matches “big 5 law firms”. Matching reads each company's description, not its industry code or its name.
RevenueBase Smart Search: RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names big 5 law firms), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
What we exclude: Companies whose own description does not clearly place them among big 5 law firms, and records with no verified work email. Companies headquartered outside Chicago are excluded even when they keep an office there.
Match quality: In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
Ranking: Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
Verification: Every listed company carries at least one verified work email, 28,869 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
Refresh: This page's figures were pulled from the company graph on September 23, 2026. Lists refresh periodically as the graph is re-checked.
Corrections: Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.

Big 5 law firms by metro in the United States

Frequently asked

What is RevenueBase Smart Search?

RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names big 5 law firms, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.

How many big 5 law firms are there based in Chicago, United States?

RevenueBase identified 492 big 5 law firms headquartered in Chicago, United States as of September 2026, matched on each company's own description of what it does rather than its industry code.

What is the largest company on this list?

Baker Mckenzie, headquartered in Chicago, tops this list with the largest team on record.

Which city in the United States has the most big 5 law firms?

New York leads the United States with 1,021 headquartered companies, followed by Chicago (492) and Los Angeles (477).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 28,869 verified decision-maker contacts tracked across these 492 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 23, 2026.

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About this data

RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.