- Chesley, Taft & Associates, LLC
- Chethik & Dellaria Consulting LLC
- Chiboys Cafe
- Chicago Architecture Foundation
- Chicago Athletic Association
- Chicago Athletic Association
- Chicago Bar Association
- Chicago Bar Foundation
- Chicago Brewhouse On The Riverwalk
- Chicago Bridal Jewelers
- Chicago Camera Specialists
- Chicago Cannabis Company
- Chicago City Storage LLC
- Chicago Cobblers
- Chicago Community Development Corporation, Ccdc
- Chicago Concessions @ Cibc Theatre
- Chicago Concessions At Nederlander Theatre
- Chicago Concessions Palace, INC.
- Chicago Cozy Comforts / Paleta Belly
- Chicago Cultural Alliance
- Chicago Curry House
- Chicago Dancemakers Forum
- Chicago Designer Closets
- Chicago Detours INC.
- Chicago Diamond Center
- Chicago Diamond Experts, INC.
- Chicago Engineers Foundation
- Chicago Event Management
- Chicago Fat Doctor & Anti-aging Clinic
- Chicago Findings INC
- Chicago Fire Football Club, LLC
- Chicago Fire Foundation
- Chicago French Press
- Chicago Gangsters And Ghosts Tours
- Chicago Gem And Jewelry Evaluation Services
- Chicago Golf Show, INC.
- Chicago Hilton & Towers
- Chicago Hire Company
- Chicago Homes One
- Chicago Human Rhythm Project
- Chicago Ink And Toner Irepair
- Chicago Invisible Setters., INC
- Chicago Jets Hockey Club, INC
- Chicago Jobs Council
- Chicago Kernel Gourmet Popcorn
- Chicago Lakefront Cruises LLC
- Chicago Latino Theater Alliance
- Chicago Loop Alliance
- Chicago Loop Nutrition, INC. DBA General Nutrition Center
- Chicago Lunchbox
- Chicago Metro Mart INC.
- Chicago Metropolitan Housing Development Corporation
- Chicago Minority Supplier Development Council
- Chicago Multi-cultural Dance Center
- Chicago Opera Theater
- Chicago Parking Meters, LLC
- Chicago Passport & Visa Expedite Services, LLC
- Chicago Pawnbroker INC.
- Chicago Poster Restoration INC
- Chicago Prime Tours
- Chicago Property Tax Appeal And Recovery
- Chicago Public Library Foundation
- Chicago Recording Company
- Chicago Recording Company
- Chicago Retroboats
- Chicago Setting Jewelers Corp.
- Chicago Sinfonietta INC.
- Chicago Sister Cities International
- Chicago Sports Novelty
- Chicago Symphony Orchestra/the Orchestral Association
- Chicago Tai Chi
- Chicago Tax Consultancy LLC
- Chicago Theater
- Chicago Theatre Group, INC.
- Chicago Trading Company
- Chicago Trolley Co.
- Chicago Twenty Something
- Chicago United Industries,ltd.
- Chicago Upscale Clean Team
- Chicago Valet
- Chicago Valet Mgmt
- Chicago Venture Partners
- Chicago Water Taxi
- Chicago Watercraft
- Chicago Yacht Club
- Chicago Youth Centers
- Chicago Youth Symphony Orchestras
- Chicago's First Lady Cruises
- Chicagoland Community Management, INC.
- Chicargo Express LLC
- Chick-fil-a
- Chick-fil-a At Millennium Park (il) In-line
- Chick-fil-a Millennium Park
- Chick-fil-a State And Lake In-line
- Chicken Planet
- Chifam, LLC.
- Children's Home & Aid
- Children's Research Triangle
- Chipotle Mexican Grill
- Chitown Food & Deli
- Chiya Chai
- Chkn - Box
- Chowbus
- Chris Martin
- Chris Watch Repair, INC.
- Christian Century
- Christopher Downes
- Christopher Romani
- Christopher Vukasin
- Christopher's Attic Vintage
- Chun Lam
- Cibc Private Wealth Advisors
- Cibc Theatre
- Cibt, INC.
- Cielo Concessions, LLC
- Cimco, A Division Of Comcast Business Services
- Circana, INC
- Circle K
- Circle K
- Citadel Enterprise Americas
- Citadel Perfumes
- Citadel Property Advisors
- Citigroup Global Markets, INC.
- Citizenm Chicago Downtown Hotel
- Citrine Informatics, INC.
- City Bee Savers
- City Loft LLC
- City Rock
- City Social
- City Staffing Services INC
- City Winery Chicago
- Civc Partners, L.P.
- Civcon Services, INC.
- Civic Consulting Alliance
- Civis Analytics, INC.
- Cjg Consulting, LLC
- Cjl Resources LLC
- Ckearedge Solutions INC.
- Clareo
- Clarity Partners
- Clarius Partners, LLC
- Clark Street Cleaners
- Claro Healthcare, LLC
- Classical Music Chicago
- Clean Windows R Us
- Clear Channel Airports
- Clear Channel Outdoor
- Clearwater Analytics, LLC
- Clemons & Company Holdings, LLC
- Cleo's Southern Cuisine
- Cleveland-cliffs Steel LLC
- Clinical Outcomes Solutions
- Clothe Me Thriftique
- Club Craftsmen
- Club Pilates South Loop
- Club Quarters
- Club Quarters Central Loop
- Cmm Food Services INC
- Cn Discounts, INC.
- Cobra Lounge
- Cochan Volant
- Cocobar
- Code Of Conduct
- Code Platoon
- Codifyd INC.
- Coeur Mining, INC.
- Cogent Communication INC
- Cogent Strategic Wealth
- Cognitive Capital, LLC
- Cohen Capital
- Cohen Financial Management Of Raymond James
- Coherent Economics, LLC
- Cohesiveft
- Collier Jewelry & Watch Sales
- Colliers
- Color In The Loop Salon LLC
- Colson Associates, INC.
- Columbia Capital Management, LLC
- Columbia College Chicago Bookstore #8331
- Columbia Wanger Asset Management LLC
- Columbia Yacht Club
- Commongrounds Workplace
- Community Desk Chicago
- Community Tax, LLC
- Comperemedia
- Competive Piping Systems INC
- Complete Legal
- Comprehensive Construction Consulting, INC.
- Compucity INC
- Computer Aid INC
- Computerized Facility Integration, LLC
- Comscore, INC.
- Comtek International, INC.
- Comvest Capital Advisors, LLC
- Con Azucar Cafe Chicago
- Concern Worldwide Us INC
- Concierge Unlimited Inernational
- Concord Sheridan LP
- Concorde
- Concrete Communication LLC