- Nimble
- Nimbus-5 LLC
- Nina
- Nippon Steel North America, INC.
- Nirav Parikh
- Niu
- Nkfi
- No Cold Feet
- No Constraint Designs
- No Vacancy
- Nomad-chicago
- Nomi
- None
- None
- None
- Nonnina
- Nora Bryant
- Nora Restaurant
- Nordic House
- Nordstrom Rack #268
- North Loop Market
- North Shore Exchange NFP
- Northwestern University Bookstore #776
- Norvax, INC.
- Norvax, LLC
- Nosey I Corp
- Nosiboo USA INC
- Not So Perfect
- Novogroder Companies INC.
- Nrs Real Estate
- Nrs Rental Property
- Ns Sales, INC.
- Ntp Wireless
- Ntt Data INC.
- Nuhaus
- Nurture Beauty
- Nutritious Earth
- Nuventures 3000
- Nv Beauty Bar
- Nyc Bagel Deli - Dearborn
- O Spa
- O'brien Harris LLC
- O'briens
- O'callaghan's
- O'dwyer Painting And Maintenance LLC
- O'leary's Public House
- Oak Street Tailors
- Obed Cleaning Services
- Obelix Restaurant
- Obesity Medicine Association
- Oc Condominium Developer LLC
- Ochi Consulting + Partners
- Octagon, INC.
- October's Very Own Merchandising Us, LP
- Odyssey Chicago River
- Off Color Brewing
- Off The Bolt
- Office Depot # 568
- Officeluv
- Offshore
- Offshore Entertainment
- Ofs
- Oh Yes Chicago
- Ohio House Motel
- Ohio Parking
- Ohr Illumination
- Oil-dri Corporation Of America
- Okamura Corporation
- Oksispark LLC
- Old Author's Bbq
- Old Jerusalem Restaurant
- Old Navy Store #5328
- Old Town Ale House INC
- Old Town Animal Care Center
- Old Town Animal Care Center
- Old Town Athletic, INC (inc.)
- Old Town Barbershop Co.
- Old Town Fish Bar
- Old Town Garden INC.
- Old Town Medspa
- Old Town Nails Salon LTD
- Old Town Oil
- Old Town Park
- Old Town Pour House
- Old Town Pub
- Old Town Smokes And Kicks
- Old Town Valet Service
- Old Town Vintage
- Olio E Piu
- Olio Gold Coast
- Olive Mediterranean Grill
- Olive Mediterranean Grill
- Olive Mediterranean Grill
- Olivo Amigo
- Olly And Arya
- Olly Olly Group LLC DBA Tag
- Olson Communications, INC.
- Olympia Cleaners
- Omega Parking, INC
- Omni Chicago Hotel
- Omnicommunications
- On Experience 7 LLC
- On The Scene Chicago
- One 100 Chicago
- One Parking
- One Parking 707
- One Superior Place
- Onshore Technology Group, INC.
- Ontario Cleaners
- Ontario Place Valet Cleaners
- Openfaster
- Oppo Home Design, LLC
- Optimal Wellness LTD
- Optimus
- Orange Skin LLC
- Orange Theory Fitness
- Orangetheory Fitness
- Orangetheory Fitness
- Orca Supplychain INC.
- Order Of Friar Servants Of Mary, USA Province, INC.
- Organic Looms
- Ori Spa River North
- Ori Spa Streeterville
- Orizzonti
- Orleans Cleaners
- Orleans Nails And Spa LLC
- Orleans Plaza Newsstand
- Orso's Restaurant
- Osaka Beauty
- Oscar Isberian Rugs, INC.
- Oscar's Shoe Recrafting
- Osco Drug Store # 3546
- Osewa Cleaners
- Oska
- Osteria Del Pastaio
- Osteria Via Stato
- Oud Coffee & Cafe
- Ouidie's Flair
- Ouray Technology Partners INC.
- Outside Magazine
- Overland Sheepskin Co., INC.
- Ow Lee Co INC
- Owlcrest
- Ox Bar & Hearth
- P O S H
- P.f. Chang's China Bistro, INC.
- P.f. Chang's To Go
- P&g Residential Services
- P3 Markets LLC
- Pac Leaders
- Pain Cave Fitness, LLC / DBA Magmile Crossfit
- Paks On The Pier
- Pallotta Tonic, LLC
- Pamela Nosse
- Panda Express #5046
- Pandora
- Pandora
- Pandora
- Panera Bread #9210
- Pangaea Information Tech
- Papa John's Pizza
- Paper Source
- Paper Source INC
- Papilon Press
- Paragon Global Initiative Foundation
- Paramount Cleaners
- Parc Chestnut Cleaners
- Paris Baguette
- Paris Baguette
- Paris Ceramics
- Paris Ceramics
- Park Hero INC.
- Park Newberry Cleaner
- Park Place Investments
- Parking At 777
- Parking Chi
- Parking Express LLC
- Parkplus
- Parkview Cleaner
- Parkview Cleaners & All Fashion
- Parley Lincoln Park
- Parliament Enterprises Limited
- Parlor Pizza Bar
- Parterre Urban Landscape Design, LLC
- Partisan
- Parto Naderi Salon Creation De Beaute / Dvida Spa
- Paskal Rudnicke Casting, INC.
- Passion House Cafe #3, LLC
- Passion Nails 1
- Patagonia
- Pathlight Mood And Anxiety Centers
- Patina Collection, LLC
- Patrick J. Dimichele
- Paul Ferrante INC
- Paul Rehder Salon LLC
- Paul Sovcik
- Paul Stuart, INC.
- Paulette Wolf Events & Entertainment, INC.
- Pauline Grace INC
- Paulson Office, LLC