| $350,000–1 million | OLIVER / HATCHER CONSTRUCTION AND DEVELOPMENT, INC. | NOVI, MI | Fifth Third Bank |
| $350,000–1 million | OLLIER MASONRY INC | Batesville, IN | Fifth Third Bank |
| $350,000–1 million | OLLIER MASONRY INC | BATESVILLE, IN | Fifth Third Bank |
| $350,000–1 million | OLSON DENTAL LABORATORY, INC. | CLINTON TOWNSHIP, MI | Fifth Third Bank |
| $150,000–350,000 | OLSON RUG COMPANY | CHICAGO, IL | Fifth Third Bank |
| $1–2 million | OLYMPIA FOOD INDUSTRIES INC | Franklin Park, IL | Fifth Third Bank |
| $1–2 million | OLYMPIA FOOD INDUSTRIES, INC. | FRANKLIN PARK, IL | Fifth Third Bank |
| $150,000–350,000 | OMEGA CASTING INC | Battle Creek, MI | Fifth Third Bank |
| $150,000–350,000 | OMEGA CASTINGS, INC. | BATTLE CREEK, MI | Fifth Third Bank |
| $350,000–1 million | OMEGA ELECTRIC CO. INC. | ELK GROVE VILLAGE, IL | Fifth Third Bank |
| $150,000–350,000 | OMEGA PRINTING INC. | Bensenville, IL | Fifth Third Bank |
| $150,000–350,000 | OMEGA PRINTING, INC. | BENSENVILLE, IL | Fifth Third Bank |
| $150,000–350,000 | OMEGA TITLE AGENCY LLC | Stow, OH | Fifth Third Bank |
| $150,000–350,000 | OMEGA TITLE LLC | STOW, OH | Fifth Third Bank |
| $350,000–1 million | OMELETTE PARTNERS INC. | Grand Rapids, MI | Fifth Third Bank |
| $350,000–1 million | OMELETTE PARTNERS, INC. | GRAND RAPIDS, MI | Fifth Third Bank |
| $1–2 million | OMG, LLC | LOUISVILLE, KY | Fifth Third Bank |
| $350,000–1 million | OMNI PRODUCTS, INC. | MCHENRY, IL | Fifth Third Bank |
| $1–2 million | OMNIPOINT US, LLC | MIAMI, FL | Fifth Third Bank |
| $1–2 million | OMS NATIONAL INSURANCE COMPANY, RISK RETENTION GROUP | SCHAUMBURG, IL | Fifth Third Bank |
| $150,000–350,000 | ON THE MARK SERVICES, INC | WORTHINGTON, OH | Fifth Third Bank |
| $150,000–350,000 | ON TIME DISTRIBUTION, LLC | DARLINGTON, SC | Fifth Third Bank |
| $150,000–350,000 | ON1 BAND LLC | Orlando, FL | Fifth Third Bank |
| $2–5 million | ONCOLOGY HEMATOLOGY CARE INC | CINCINNATI, OH | Fifth Third Bank |
| $350,000–1 million | ONE OFF HOSPITALITY GROUP LTD | Chicago, IL | Fifth Third Bank |
| $350,000–1 million | ONE OFF HOSPITALITY GROUP LTD | CHICAGO, IL | Fifth Third Bank |
| $150,000–350,000 | ONE WAY MINISTRIES | Aurora, IL | Fifth Third Bank |
| $350,000–1 million | ONE WAY SAFETY LLC | La Grange, IL | Fifth Third Bank |
| $350,000–1 million | ONE WAY SAFETY, LLC | LA GRANGE, IL | Fifth Third Bank |
| $5–10 million | ONE10 LLC | MINNEAPOLIS, MN | Fifth Third Bank |
| $350,000–1 million | ONEFRO, LLC. | CHICAGO, IL | Fifth Third Bank |
| $350,000–1 million | ONESIGHT | MASON, OH | Fifth Third Bank |
| $350,000–1 million | ONESIGHT AN OHIO NONPROFIT CORPORATION | Mason, OH | Fifth Third Bank |
| $350,000–1 million | ONESOURCE EMPLOYEE MANAGEMENT, LLC | CHAGRIN FALLS, OH | Fifth Third Bank |
| $1–2 million | ONLINE TECH STORES LLC | Reno, NV | Fifth Third Bank |
| $1–2 million | ONLINE TECH STORES LLC | Reno, NV | Fifth Third Bank |
| $150,000–350,000 | ONPOWER INC | Lebanon, OH | Fifth Third Bank |
| $350,000–1 million | ONPOWER INC | LEBANON, OH | Fifth Third Bank |
| $150,000–350,000 | ONSI-ROESCH LLC | Dunwoody, GA | Fifth Third Bank |
| $150,000–350,000 | ONSITE HEALTHCARE INC SC | LINCOLNWOOD, IL | Fifth Third Bank |
| $150,000–350,000 | ONTIME HEATING AND AIRCONDITIONING INC. | Henderson, KY | Fifth Third Bank |
| $150,000–350,000 | ONTIME HEATING AND AIRCONDITIONING, INC. | HENDERSON, KY | Fifth Third Bank |
| $150,000–350,000 | ONWARD NEIGHBORHOOD HOUSE | CHICAGO, IL | Fifth Third Bank |
| $1–2 million | OOSTERBAAN & SONS CO. | POSEN, IL | Fifth Third Bank |
| $1–2 million | OOSTERBAAN & SONS CO. | Posen, IL | Fifth Third Bank |
| $150,000–350,000 | OP4G INC | PORTSMOUTH, NH | Fifth Third Bank |
| $150,000–350,000 | OPA1 INC. | Traverse City, MI | Fifth Third Bank |
| $350,000–1 million | OPC CONSTRUCTION INC. | Wood Dale, IL | Fifth Third Bank |
| $350,000–1 million | OPC CONSTRUCTION, INC. | WOOD DALE, IL | Fifth Third Bank |
| $5–10 million | OPEN ACCESS TECHNOLOGY INTERNATIONAL, INC. | MINNEAPOLIS, MN | Fifth Third Bank |
| $350,000–1 million | OPEN DOOR CHRISTIAN SCHOOLS INC | Elyria, OH | Fifth Third Bank |
| $150,000–350,000 | OPENFINANCE HOLDINGS, INC. | Chicago, IL | Fifth Third Bank |
| $150,000–350,000 | OPPORTUNITY FRANCHISING, INC. | SCHAUMBURG, IL | Fifth Third Bank |
| $350,000–1 million | OPT STAFFING LLC | Cincinnati, OH | Fifth Third Bank |
| $1–2 million | OPTIMAL STAFFING SOLUTIONS INC. | Lansing, MI | Fifth Third Bank |
| $1–2 million | OPTIMAL STAFFING SOLUTIONS, INC. | LANSING, MI | Fifth Third Bank |
| $350,000–1 million | OPTIMIZED ASPECTS LLC | San Francisco, CA | Fifth Third Bank |
| $350,000–1 million | OPTIMIZED ASPECTS, LLC | SAN FRANCISCO, CA | Fifth Third Bank |
| $2–5 million | OPTIMUM STAFFING, INC. | LISLE, IL | Fifth Third Bank |
| $350,000–1 million | OPTIMUM WATER SOLUTIONS INC. | Oviedo, FL | Fifth Third Bank |
| $350,000–1 million | OPTIMUM WATER SOLUTIONS, INC. | OVIEDO, FL | Fifth Third Bank |
| $150,000–350,000 | OPTOMETRY PC | CLINTON TOWNSHIP, MI | Fifth Third Bank |
| $350,000–1 million | ORAL & MAXILLOFACIAL SURGERY ASSOCIATES OF WESTERN MICHIGAN | GRAND RAPIDS, MI | Fifth Third Bank |
| $350,000–1 million | ORAL SURGERY ASSOCIATES, P.C. | GRAND RAPIDS, MI | Fifth Third Bank |
| $150,000–350,000 | ORBIS HOLDING GROUP | SAINT CLAIR, MI | Fifth Third Bank |
| $150,000–350,000 | ORBIS HOLDINGS GROUP L.L.C. | Saint Clair, MI | Fifth Third Bank |
| $150,000–350,000 | ORBIT MOVERS ERECTORS, INC. | Dayton, OH | Fifth Third Bank |
| $150,000–350,000 | ORBIT SYSTEMS INC | GALENA, OH | Fifth Third Bank |
| $150,000–350,000 | ORBIT SYSTEMS INC | Galena, OH | Fifth Third Bank |
| $1–2 million | ORCHARD LAKE SCHOOLS | ORCHARD LAKE, MI | Fifth Third Bank |
| $1–2 million | ORCHARD LAKE SCHOOLS S.S CYRIL & METHODIUS SEMINARY | Orchard Lake, MI | Fifth Third Bank |
| $150,000–350,000 | ORDER MEDIA SOLUTIONS LLC | FORT LAUDERDALE, FL | Fifth Third Bank |
| $1–2 million | OREGON FORD, INC | OREGON, OH | Fifth Third Bank |
| $350,000–1 million | OREGON LIVING & REHABILITATION CENTER, LLC | OREGON, IL | Fifth Third Bank |
| $1–2 million | ORGANIZED LIVING, INC | CINCINNATI, OH | Fifth Third Bank |
| $150,000–350,000 | ORIBELLO ENTERPRISES LLC | Fort Wayne, IN | Fifth Third Bank |
| $150,000–350,000 | ORIBELLO ENTERPRISES, LLC | FORT WAYNE, IN | Fifth Third Bank |
| $150,000–350,000 | ORIGIN IV ENTERPRISES LLC | BELMONT, NC | Fifth Third Bank |
| $150,000–350,000 | ORIGO BRANDING COMPANY INC | COLUMBUS, OH | Fifth Third Bank |
| $350,000–1 million | ORION INDUSTRIES, LTD. | CHICAGO, IL | Fifth Third Bank |
| $150,000–350,000 | ORION MANAGEMENT INC | NORTH CANTON, OH | Fifth Third Bank |
| $350,000–1 million | ORLAND PARK ORTHOPEDICS, S.C. | ORLAND PARK, IL | Fifth Third Bank |
| $350,000–1 million | ORLANDO REGIONAL REALTOR ASSOCIATION INC. | Orlando, FL | Fifth Third Bank |
| $350,000–1 million | ORLANDO REPERTORY THEATRE | Orlando, FL | Fifth Third Bank |
| $150,000–350,000 | ORLEANS, CANTY, NOVY, LLC | CHICAGO, IL | Fifth Third Bank |
| $150,000–350,000 | ORO MANUFACTURING COMPANY | MONROE, NC | Fifth Third Bank |
| $150,000–350,000 | ORSOLINI'S WELDING & FABRICATING COMPANY | CHICAGO, IL | Fifth Third Bank |
| $1–2 million | ORTHOBANC, LLC | Hixon, TN | Fifth Third Bank |
| $350,000–1 million | ORVILLE OSBORNE HOLDINGS, INC | FAIRFIELD, OH | Fifth Third Bank |
| $350,000–1 million | OSI ACQUISITION CORPORATION | LOUISVILLE, KY | Fifth Third Bank |
| $350,000–1 million | OSTERWISCH COMPANY, INC | CINCINNATI, OH | Fifth Third Bank |
| $2–5 million | OTGP MANAGMENT, LLC | CHAPEL HILL, NC | Fifth Third Bank |
| $350,000–1 million | OTSEGO CLUB FOOD AND BEVERAGE LLC | Gaylord, MI | Fifth Third Bank |
| $350,000–1 million | OTSEGO CLUB FOOD AND BEVERAGE, LLC | LEWISTON, MI | Fifth Third Bank |
| $150,000–350,000 | OUR LADY OF GRACE CATHOLIC SCHOOL | CINCINNATI, OH | Fifth Third Bank |
| $150,000–350,000 | OUR LADY OF GUADALUPE | Chicago, IL | Fifth Third Bank |
| $150,000–350,000 | OUR LADY OF GUADALUPE | Chicago, IL | Fifth Third Bank |
| $150,000–350,000 | OUR LADY OF LOURDES CATHOLIC CHURCH, INDIANAPOLIS IN | Indianapolis, IN | Fifth Third Bank |
| $350,000–1 million | OUR LADY OF LOURDES CHURCH | Cincinnati, OH | Fifth Third Bank |
| $350,000–1 million | OUR LADY OF THE GREENWOOD CATHOLIC CHURCH, INC. | GREENWOOD, IN | Fifth Third Bank |