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Top 37 consulting firms in Connecticut

Tamtam tracks 37 consulting firms headquartered in Connecticut. This list ranks all of them by number of employees on LinkedIn, led by Gartner, TRC Companies, Inc. and Electronic Data Systems. Their median headcount is 405. Half of them were founded in 2000 or later. The most common headquarters are Stamford (9), Hartford (4) and Middletown (2).

馃嚭馃嚫 Connecticut37 companiesUpdated Nov 2, 2026
#CompanyIndustryHeadquarters EmployeesFounded
1
Gartnergartner.com

A global company providing expert-led research and data-driven insights to help executives make faster, smarter decisions and achieve stronger performance

Information Services 馃嚭馃嚫 Stamford 22,206 1979
2
TRC Companies, Inc.trccompanies.com

Providing advisory, consulting, construction, engineering, and management services to help clients adapt and achieve sustainable, impactful results.

Environmental Services 馃嚭馃嚫 Windsor 7,463 1969
3
Electronic Data Systemsdxc.com

A global company founded in 1962 offering electronic data processing management personnel and computer hardware, focusing on large corporations and government contracts

IT Services and IT Consulting 馃嚭馃嚫 West Hartford 3,809 1962
4
Daymondaymon.com

Provides end-to-end private brand development services including strategy, product development, quality assurance, supplier management, sales, and branding solutions.

Business Consulting and Services 馃嚭馃嚫 Stamford 2,262 1970
5
ISG (Information Services Group)isg-one.com

Global AI-focused technology research and advisory firm helping organizations optimize technology investments and achieve operational excellence and growth.

Information Services 馃嚭馃嚫 Stamford 2,189 2006
6
Rizingrizing.com

A global SAP partner offering strategy, implementation, and support for SAP HCM, EAM, and Retail/Fashion industries, driving business transformation with industry expertise

IT Services and IT Consulting 馃嚭馃嚫 Stamford 989 2006
7
MMA (Marketing Management Analytics)mma.com

Provides unified marketing and commercial measurement, data management, software, and consulting services to enhance brand value and revenue growth.

Advertising Services 馃嚭馃嚫 Norwalk 911 1988
8
SDG Corporationsdgc.com

A global provider of technology and consulting services specializing in cybersecurity, identity, and risk management solutions for enterprises worldwide

IT Services and IT Consulting 馃嚭馃嚫 Norwalk 754 1993
9
Crisil Coalition Greenwichgreenwich.com

A leading provider of strategic benchmarking and analytics to the financial services industry, offering actionable insights to improve business performance

Financial Services 馃嚭馃嚫 Stamford 660 n/a
10
LIMRAlimra.com

A global organization providing research, consulting, and professional development services to insurance and financial companies worldwide, helping them improve marketing and distribution effectiveness

Financial Services 馃嚭馃嚫 Windsor 648 1916
11
SimiTreesimitreehc.com

SimiTree provides a wide range of support services and consulting to post-acute organizations in the healthcare industry to improve performance and revenue

Hospitals and Health Care 馃嚭馃嚫 Hamden 526 2011
12
Butler Aerospace & Defensebutler.com

Specializing in state-of-the-art, cost-optimized solutions, we cater to Aerospace, Defense, and Federal markets by offering high-end engineering talent and flexible business models

Engineering Services 馃嚭馃嚫 Shelton 521 1947
13
Rizing Consumer Industriesrizing.com

Leader in retail and consumer products for SAP software, providing specialized solutions and consulting services to optimize SAP experience worldwide

IT Services and IT Consulting 馃嚭馃嚫 Stamford 505 n/a
14
BL Companiesblcompanies.com

Company offering integrated architecture, engineering, environmental sciences, land surveying, and planning services with a focus on quality, employee ownership, and work-life balance

Civil Engineering 馃嚭馃嚫 Meriden 498 1986
15
USI Consulting Groupusicg.com

A leading retirement plan consulting and benefits administration firm, providing comprehensive guidance and innovative solutions for employers and their employees nationwide

Financial Services 馃嚭馃嚫 Glastonbury 494 n/a
16
Fuss & O'Neillfando.com

A full-service engineering and planning firm with over 95 years of experience, serving public and private sectors across the East Coast

Civil Engineering 馃嚭馃嚫 Hartford 484 1924
17
LogicSource, Inc.logicsource.com

LogicSource specializes in procurement services for indirect goods, helping brands optimize spending through expertise, technology, and strategic partnerships.

Business Consulting and Services 馃嚭馃嚫 Westport 423 2009
18
AI Engineers, Inc.aiengineers.com

A multidisciplinary engineering firm providing innovative solutions for infrastructure needs, prioritizing accountability, entrepreneurship, innovation, inclusiveness, and transparency to benefit communities

Civil Engineering 馃嚭馃嚫 Middletown 411 1991
19
Lockwoodthelockwoodgrp.com

The company collaborates with pharmaceutical, biotech, and medical device industries to create evidence-based, impactful strategies and communications for brand development

Advertising Services 馃嚭馃嚫 Stamford 405 2007
20
Zaelabzaelab.com

Highly-skilled digital partner advising global B2B organizations on delivering next-generation digital solutions to market

Business Consulting and Services 馃嚭馃嚫 Westport 391 2010
21
Comply Regulatory Servicescomply.com

An advanced provider of compliance and registration products and services for financial institutions, offering expert consulting and education to navigate regulatory requirements

Financial Services 馃嚭馃嚫 Lakeville 312 1984
22
Consulting Engineering Services (CES)ceseng.com

Specializes in sustainable MEP/FP engineering for commercial and residential buildings, focusing on energy efficiency, net-zero, and resilient design.

Engineering Services 馃嚭馃嚫 Middletown 306 1994
23
EverestDX Inceverestdx.com

A digital platform services company specializing in orchestration, intelligent operations, and AI-powered analytics for enterprise IT to enable seamless digital transformation

Software Development 馃嚭馃嚫 Stamford 280 2018
24
MTU Aero Engines North Americamtuusa.com

Specializing in complete engineering services for the gas turbine industry, providing design, analysis, project management, and aftermarket engineering solutions tailored to individual needs

Aviation and Aerospace Component Manufacturing 馃嚭馃嚫 Rocky Hill 220 2000
25
Maganti IT Resources, LLCmitresource.com

A leading IT Software development and consulting firm, specializing in designing and delivering technology solutions to help clients gain a competitive edge

IT Services and IT Consulting 馃嚭馃嚫 Waterbury 198 2004
26
Cyma Systems Inccymasys.com

A technology solutions firm in Connecticut offering services to mid-sized and Fortune 1000 businesses, focused on profitability, innovation, cost reduction, and customer satisfaction

IT Services and IT Consulting 馃嚭馃嚫 Manchester 108 2006
27
Visionary Innovative Technology Solutions LLCvitsus.com

A staffing and consulting firm partnering with clients globally to improve work efficiency and foster relationships across various industries

IT Services and IT Consulting 馃嚭馃嚫 Plantsville 99 2017
28
Titan Energytitanenergyne.com

A leading energy consultant providing procurement, on-site generation, and tailored solutions to nonprofit, commercial, and industrial clients across the US

Utilities 馃嚭馃嚫 Hartford 68 2001
29
Apple Consulting Group Incappleconsultinggroup.com

Innovative consulting firm specializing in new technology, cloud solutions, digital transformation, and business systems improvement across various sectors

IT Services and IT Consulting 馃嚭馃嚫 Trumbull 22 2010
30
TenX AItenx.ai

A small team of data geeks passionate about solving business problems with artificial intelligence, helping organizations globally explore and execute data opportunities

IT Services and IT Consulting 馃嚭馃嚫 Stamford 13 2011
31
Competitive Resources, Inc.cri-energy.com

A seasoned provider of energy efficiency services, including residential and commercial retrofits, quality assurance, database design, program planning, evaluation, and marketing

Utilities 馃嚭馃嚫 Yalesville 13 1988
32
Winchester Capitalwinchestercapital.com

Privately-owned investment banking firm offering strategic advisory services, international asset management, and expertise in cross-border mergers & acquisitions for global clients

Investment Banking 馃嚭馃嚫 New Haven 11 1986
33
Facilities Engineering Associates, P.C.feace.com

A leading engineering consultancy specializing in designing and commissioning datacenters, mission critical facilities, and utility systems for Fortune 500 clients since 1987

Construction 馃嚭馃嚫 Farmington 10 1987
34
Global Finesseglobalfinesse.com

Specialist consultancy providing investment and risk management systems for global banks, insurance companies, and asset management firms in the financial services industry

Financial Services 馃嚭馃嚫 Hartford 9 2004
35
Ketchbrook Analyticsketchbrookanalytics.com

New England analytics consulting firm specializing in data strategy, business intelligence, predictive modeling, model validation, and process automation services

IT Services and IT Consulting 馃嚭馃嚫 Hartford 6 2019
36
MHR Development, LLCmhrdevelopment.com

Specializing in sustainable energy solutions for buildings and campuses, focusing on renewable sources and energy efficiency

Environmental Services 馃嚭馃嚫 New Canaan 3 2004
37
zlc technologyzlctechnology.com

Business and Technology consulting firm specializing in Digital Transformation, offering expertise in voice, network, cloud, and security through various technology providers Trusted IT advisor

IT Services and IT Consulting 馃嚭馃嚫 Southington 3 n/a

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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 2, 2026.

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