| $350,000–1 million | JENKINS & KLING, P.C. | SAINT LOUIS, MO | 1st Advantage Bank |
| $150,000–350,000 | JEROME L HOWE INC | SAINT LOUIS, MO | Triad Bank |
| $350,000–1 million | JERRY ACKERMAN MOTOR COMPANY, INC. | SAINT LOUIS, MO | St. Louis Bank |
| $2–5 million | JEWISH COMMUNITY CENTER | SAINT LOUIS, MO | Enterprise Bank & Trust |
| $350,000–1 million | JEWISH FAMILY SERVICES OF ST LOUIS | SAINT LOUIS, MO | Busey Bank |
| $1–2 million | JEWISH FEDERATION OF ST. LOUIS | SAINT LOUIS, MO | Royal Banks of Missouri |
| $1–2 million | JEWISH FEDERATION OF ST. LOUIS | SAINT LOUIS, MO | U.S. Bank, National Association |
| $350,000–1 million | JH BERRA ENGINEERING & SURVEYING CO. INC | SAINT LOUIS, MO | Midwest BankCentre |
| $350,000–1 million | JH BERRA PAVING CO INC | SAINT LOUIS, MO | Midwest BankCentre |
| $150,000–350,000 | JH HORSEMAN GROUP, LLC | SAINT LOUIS, MO | Peoples National Bank, National Association |
| $150,000–350,000 | JIM BUTLER ITALIA LLC | SAINT LOUIS, MO | Enterprise Bank & Trust |
| $150,000–350,000 | JIM'S HEAVY HAULING, LLC | SAINT LOUIS, MO | Community First Bank of the Heartland |
| $150,000–350,000 | JJF & C, LLC | SAINT LOUIS, MO | Commerce Bank |
| $150,000–350,000 | JK PULLEY CO. INC | SAINT LOUIS, MO | Carrollton Bank |
| $150,000–350,000 | JKC, INC | SAINT LOUIS, MO | Montgomery Bank |
| $150,000–350,000 | JL HOCHMAN COMPANY LLC | SAINT LOUIS, MO | Busey Bank |
| $350,000–1 million | JOCOR ENTERPRISES, INC. | SAINT LOUIS, MO | Triad Bank |
| $150,000–350,000 | JOE-K USED CARS | SAINT LOUIS, MO | The Central Trust Bank |
| $150,000–350,000 | JOEY B'S 3 INC. | SAINT LOUIS, MO | Carrollton Bank |
| $1–2 million | JOHN BENDER INCORPORATED | SAINT LOUIS, MO | First Mid Bank & Trust, National Association |
| $350,000–1 million | JOHN D MCGURKS INC | SAINT LOUIS, MO | Lindell Bank & Trust Company |
| $2–5 million | JOHN HENRY FOSTER COMPANY OF ST LOUIS INC | SAINT LOUIS, MO | Busey Bank |
| $350,000–1 million | JOHN J. CONNELL | SAINT LOUIS, MO | Enterprise Bank & Trust |
| $2–5 million | JOHN J. SMITH MASONRY COMPANY | SAINT LOUIS, MO | The Central Trust Bank |
| $150,000–350,000 | JOHN STEURER PLASTERING CO INC | SAINT LOUIS, MO | U.S. Bank, National Association |
| $150,000–350,000 | JOHN VAN DOREN, LLC | SAINT LOUIS, MO | First Bank |
| $150,000–350,000 | JOHNNIE BROCK'S GREETING CARDS & GIFT SH | SAINT LOUIS, MO | Bank of Franklin County |
| $350,000–1 million | JOHNSON CLARKE, INC. | SAINT LOUIS, MO | Midwest BankCentre |
| $350,000–1 million | JOINT HEALTH, LLC | SAINT LOUIS, MO | First Bank |
| $350,000–1 million | JON ZURCHER | SAINT LOUIS, MO | PNC Bank, National Association |
| $150,000–350,000 | JONATHAN A SHANKER & BRIAN A SCHLUETER DMD MS PC | SAINT LOUIS, MO | Lindell Bank & Trust Company |
| $350,000–1 million | JOSEPH CAESAR INC | SAINT LOUIS, MO | Midwest BankCentre |
| $350,000–1 million | JOSEPH H. BEETZ PLUMBING COMPANY INC | SAINT LOUIS, MO | PNC Bank, National Association |
| $150,000–350,000 | JOST BUILDERS, LLC | SAINT LOUIS, MO | Carrollton Bank |
| $350,000–1 million | JPAM CONSULTING, INC. | SAINT LOUIS, MO | Busey Bank |
| $350,000–1 million | JPAM MGMT & CONSULTING, INC. | SAINT LOUIS, MO | Busey Bank |
| $150,000–350,000 | JSB TAPAWINGO HOLDINGS LLC | SAINT LOUIS, MO | Cass Commercial Bank |
| $150,000–350,000 | JSC INC | SAINT LOUIS, MO | Carrollton Bank |
| $150,000–350,000 | JTOH, INC | SAINT LOUIS, MO | Carrollton Bank |
| $150,000–350,000 | JTW RESTOATION SERVICES, INC | SAINT LOUIS, MO | St. Louis Bank |
| $1–2 million | JUDEVINE, INC. | SAINT LOUIS, MO | First Bank |
| $150,000–350,000 | JUMBY BAY STUDIOS, LLC | SAINT LOUIS, MO | The Central Trust Bank |
| $150,000–350,000 | JUNIPER RESTAURANT, LLC | SAINT LOUIS, MO | The Central Trust Bank |
| $150,000–350,000 | JUNK DOCTORS LLC | SAINT LOUIS, MO | Enterprise Bank & Trust |
| $150,000–350,000 | JURISTEMPS, INC. | SAINT LOUIS, MO | The Central Trust Bank |
| $150,000–350,000 | JUST AROUND THE CORNER, INC | SAINT LOUIS, MO | Enterprise Bank & Trust |
| $350,000–1 million | JUSTINE PETERSEN HOUSING & REINVESTMENT CORPORATION | SAINT LOUIS, MO | Midwest BankCentre |
| $150,000–350,000 | JW MECHANICAL LLC | SAINT LOUIS, MO | The Bank of Houston |
| $350,000–1 million | JW SOFTWARE, INC. | SAINT LOUIS, MO | The Central Trust Bank |
| $150,000–350,000 | JX. RESTAURANTS, INC | SAINT LOUIS, MO | U.S. Bank, National Association |
| $350,000–1 million | K & S ASSOCIATES, INC. | SAINT LOUIS, MO | Commerce Bank |
| $350,000–1 million | K. HALL STUDIO LLC | SAINT LOUIS, MO | Busey Bank |
| $2–5 million | KAEMMERLEN ELECTRIC CO. | SAINT LOUIS, MO | Cass Commercial Bank |
| $350,000–1 million | KAEMMERLEN PARTS & SERVICE INC | SAINT LOUIS, MO | Citizens Bank |
| $150,000–350,000 | KAF LLC | SAINT LOUIS, MO | Enterprise Bank & Trust |
| $350,000–1 million | KAI BUILD, LLC | SAINT LOUIS, MO | Carrollton Bank |
| $350,000–1 million | KAI / ALLIANCE, LC | SAINT LOUIS, MO | Carrollton Bank |
| $150,000–350,000 | KAI 360 CONSTRUCTION SERVICES LLC | SAINT LOUIS, MO | Carrollton Bank |
| $150,000–350,000 | KAI DESIGN & BUILD ENTERPRISES LLC | SAINT LOUIS, MO | Carrollton Bank |
| $350,000–1 million | KAI ENGINEERING LLC | SAINT LOUIS, MO | Carrollton Bank |
| $1–2 million | KALDIS INC | SAINT LOUIS, MO | Enterprise Bank & Trust |
| $150,000–350,000 | KAMYKOWSKI GAVIN & SMITH PC | SAINT LOUIS, MO | PNC Bank, National Association |
| $350,000–1 million | KARPEL COMPUTER SYSTEMS INC | SAINT LOUIS, MO | Bank Star |
| $150,000–350,000 | KARR BICK CONSTRUCTION | SAINT LOUIS, MO | Montgomery Bank |
| $150,000–350,000 | KARR BICK KITCHEN & BATH | SAINT LOUIS, MO | Montgomery Bank |
| $150,000–350,000 | KAUFMAN BROADCAST SERVICES CORPORATION | SAINT LOUIS, MO | Carrollton Bank |
| $350,000–1 million | KB SPECIAL EVENTS, LLC | SAINT LOUIS, MO | Enterprise Bank & Trust |
| $2–5 million | KCI CONSTRUCTION COMPANY | SAINT LOUIS, MO | Carrollton Bank |
| $350,000–1 million | KDG REAL ESTATE, LLC | SAINT LOUIS, MO | Commerce Bank |
| $150,000–350,000 | KDM ENTERPRISES, LLC | SAINT LOUIS, MO | Peoples National Bank, National Association |
| $150,000–350,000 | KEEFE & GRIFFITHS, PC | SAINT LOUIS, MO | UMB Bank, National Association |
| $5–10 million | KELLY MITCHELL GROUP, INC. | SAINT LOUIS, MO | Busey Bank |
| $150,000–350,000 | KEMOLL'S CHOPHOUSE, LLC | SAINT LOUIS, MO | Peoples National Bank, National Association |
| $350,000–1 million | KENNEDY PAINTING LLC | SAINT LOUIS, MO | Bank of America, National Association |
| $1–2 million | KENNELWOOD VILLAGE INC | SAINT LOUIS, MO | Commerce Bank |
| $350,000–1 million | KENNEY DESIGNER RESOURCES, INC. | SAINT LOUIS, MO | Triad Bank |
| $150,000–350,000 | KENRICK DESIGN/CONSTRUCTION SERVICES, INC | SAINT LOUIS, MO | Bank of Franklin County |
| $350,000–1 million | KENT PLUMBING, INC. | SAINT LOUIS, MO | Peoples Savings Bank of Rhineland |
| $150,000–350,000 | KERN MEAT CO., INC. | SAINT LOUIS, MO | St. Louis Bank |
| $150,000–350,000 | KESSLER CONTAINERS LTD | SAINT LOUIS, MO | Bank of America, National Association |
| $150,000–350,000 | KEY MANAGEMENT COMPANY OF MISSOURI | SAINT LOUIS, MO | Carrollton Bank |
| $1–2 million | KEYSER ENTERPRISES 1, LP | SAINT LOUIS, MO | Peoples National Bank, National Association |
| $1–2 million | KEYSTONE TEMPORARY ASSIGNMENT GROUP, INC | SAINT LOUIS, MO | The Central Trust Bank |
| $150,000–350,000 | KICKING COW PROMOTIONS, INC. | SAINT LOUIS, MO | Justine Petersen Housing & Reinvestment Corporation |
| $150,000–350,000 | KIDS IN THE MIDDLE INC | SAINT LOUIS, MO | PNC Bank, National Association |
| $150,000–350,000 | KIEFER BONFANTI & CO. LLP | SAINT LOUIS, MO | Triad Bank |
| $150,000–350,000 | KIENSTRA 44, LLC | SAINT LOUIS, MO | Great Southern Bank |
| $350,000–1 million | KIENSTRA CO. | SAINT LOUIS, MO | Triad Bank |
| $150,000–350,000 | KIENSTRA CONCRETE, INC. | SAINT LOUIS, MO | Great Southern Bank |
| $150,000–350,000 | KIENSTRA READY MIX OF O'FALLON, INC. | SAINT LOUIS, MO | Triad Bank |
| $150,000–350,000 | KIKU OBATA & COMPANY | SAINT LOUIS, MO | Commerce Bank |
| $150,000–350,000 | KIMMERON INC. | SAINT LOUIS, MO | Midwest Regional Bank |
| $150,000–350,000 | KING FILTRATION TECHNOLOGIES, INC | SAINT LOUIS, MO | Carrollton Bank |
| $350,000–1 million | KINGDOM HOUSE | SAINT LOUIS, MO | Carrollton Bank |
| $150,000–350,000 | KINGSTON DENTAL CENTER-RONALD K. GREIF D.D.S., P.C. | SAINT LOUIS, MO | UMB Bank, National Association |
| $2–5 million | KIPP ST. LOUIS | SAINT LOUIS, MO | Commerce Bank |
| $2–5 million | KIRBERG ROOFING, INC | SAINT LOUIS, MO | UMB Bank, National Association |
| $150,000–350,000 | KIRKWOOD AUTO GLASS, INC. | SAINT LOUIS, MO | Enterprise Bank & Trust |
| $150,000–350,000 | KIRKWOOD HEATING AND AIR CONDITIONING CO., INC. | SAINT LOUIS, MO | UMB Bank, National Association |
| $150,000–350,000 | KIRKWOOD UNITED METHODIST CHURCH | SAINT LOUIS, MO | Commerce Bank |