| OROmco Roll Forming Plus - Wickliffe | Wickliffe | OH | — | ◇ UNVERIFIED |
| OCOmega Consolidated Corporation | Hilton | NY | — | ◇ UNVERIFIED |
| OMOmega Machine & Tool, INC. | Mentor | OH | — | ◇ UNVERIFIED |
| OSOmega Steel Products, INC | Jemison | AL | — | ◇ UNVERIFIED |
| OTOmega Tool CO | Saint Louis | MO | — | ◇ UNVERIFIED |
| OMO & M Fabricators, LLC | Pensacola | FL | — | ◇ UNVERIFIED |
| OIOmg INC | Agawam | MA | — | ◇ UNVERIFIED |
| OIOmg, INC. Dba Hickman Engineered Systems | Arden | NC | — | ◇ UNVERIFIED |
| OMOm Machine & Tool LLC | Portland | OR | — | ◇ UNVERIFIED |
| OCOmni CORP Ii | Saint Augustine | FL | — | ◇ UNVERIFIED |
| OOmniduct | Everett | WA | — | ◇ UNVERIFIED |
| OAOmniduct Arlington | Arlington | WA | — | ◇ UNVERIFIED |
| OAOmniduct Az, LLC | Phoenix | AZ | — | ◇ UNVERIFIED |
| OIOmni Industrial Services | Buffalo | WV | — | ◇ UNVERIFIED |
| OOmnimax | Gridley | IL | — | ◇ UNVERIFIED |
| OIOmnimax International, INC. | Ivyland | PA | — | ◇ UNVERIFIED |
| OIOmnimax International, LLC Dba Millennium Metals | Jacksonville | FL | — | ◇ UNVERIFIED |
| OMOmni Measurement Systems | Winooski | VT | — | ◇ UNVERIFIED |
| OPOmni Precision | Houston | TX | — | ◇ UNVERIFIED |
| OPOmni Precision, INC. | Houston | TX | — | ◇ UNVERIFIED |
 Omni Services | Falconer | NY | — | ◇ UNVERIFIED |
| OPOn-board Pmo, Corporation | Valley View | OH | — | ◇ UNVERIFIED |
| ODOn Demand Edm INC | Blaine | MN | — | ◇ UNVERIFIED |
| OMO'neal Manufacturing Services | Cedar Falls | IA | — | ◇ UNVERIFIED |
| OMO'neal Manufacturing Services | Indianapolis | IN | — | ◇ UNVERIFIED |
| OEOne Ez Post LLC | Kingsport | TN | — | ◇ UNVERIFIED |
| OTOneida Tool Corporation | Redford | MI | — | ◇ UNVERIFIED |
| OROne Rig Design LLC | Poland | ME | — | ◇ UNVERIFIED |
| OMOneto Metal Products CORP | Sacramento | CA | — | ◇ UNVERIFIED |
| OTOne Ton Welding, Inc. | Panama | IA | — | ◇ UNVERIFIED |
| OAOnex Automation | Duarte | CA | — | ◇ UNVERIFIED |
| OSOney Sheetmetal INC | Fort Myers | FL | — | ◇ UNVERIFIED |
| OFOnGuard Fence Systems, Ltd. | Moorestown | NJ | — | ◇ UNVERIFIED |
| ONO. Norheim Corporation | Douglassville | PA | — | ◇ UNVERIFIED |
| OPOn Point Construction Services, INC. | Dover | FL | — | ◇ UNVERIFIED |
| ONO & N Rotary Screen Engraving | Pico Rivera | CA | — | ◇ UNVERIFIED |
| OCOnsite Calibartion Service INC | Louisville | KY | — | ◇ UNVERIFIED |
| OCOn-site Custom Fabrication INC. | Hendersonville | TN | — | ◇ UNVERIFIED |
| OSOn Spot Portable Machine CO INC | Livonia | MI | — | ◇ UNVERIFIED |
 On The Edge MFG, Inc | Kittanning | PA | — | ◇ UNVERIFIED |
| OTOn the Level Fabrication, LLC | Winder | GA | — | ◇ UNVERIFIED |
| OTOn the Mean, Machine, LLC | Grand Rapids | OH | — | ◇ UNVERIFIED |
| OTOn Time Fab INC | Saint Joseph | KY | — | ◇ UNVERIFIED |
| OLOntrac Logistics INC | Fremont | CA | — | ◇ UNVERIFIED |
| OFOostman Fabricating & Welding, INC. | Westmont | IL | — | ◇ UNVERIFIED |
| OFOpc Fabrication and Equipment, INC. (fn) | Phoenix | AZ | — | ◇ UNVERIFIED |
| OOOpEx OpCo Inc. | Minneapolis | MN | — | ◇ UNVERIFIED |
| OIOPMP, Inc. | Tracy | CA | — | ◇ UNVERIFIED |
| OTOp Tanks LLC | Pleasant View | UT | — | ◇ UNVERIFIED |
| OTOptics Technology, INC. | Pittsford | NY | — | ◇ UNVERIFIED |
| OPOptima Precision, Inc. | San Jose | CA | — | ◇ UNVERIFIED |
| OPOptimum Parts Company | Holyoke | MA | — | ◇ UNVERIFIED |
| OPOrange Park Machine, INC. | Orange Park | FL | — | ◇ UNVERIFIED |
| OSOrange State Steel | Bartow | FL | — | ◇ UNVERIFIED |
| OSOrange State Steel Construction, INC. | Riverview | FL | — | ◇ UNVERIFIED |
| OSOrange Steel Roofing Products | Orange | VA | — | ◇ UNVERIFIED |
| OLOrangeworks LLC | Fort Wayne | IN | — | ◇ UNVERIFIED |
| OCOrco Construction Supply | Bloomington | CA | — | ◇ UNVERIFIED |
| ODOrdaz Drilling | Paramount | CA | — | ◇ UNVERIFIED |
| ODOreco Duct System INC | Baldwin Park | CA | — | ◇ UNVERIFIED |
| OIOregon Industrial Repair INC | Salem | OR | — | ◇ UNVERIFIED |
| OMOregon Machine Works, INC. | Canby | OR | — | ◇ UNVERIFIED |
| OPOregon Pacific Structural Fabrication, LLC | Mulino | OR | — | ◇ UNVERIFIED |
| OPOregon Precision Manufacturing INC | Sherwood | OR | — | ◇ UNVERIFIED |
| OSOreland Sheet Metal Inc | Huntingdon Valley | PA | — | ◇ UNVERIFIED |
| OTOrganic Transit INC. | Durham | NC | — | ◇ UNVERIFIED |
| OUOrica USA INC | Marion | IL | — | ◇ UNVERIFIED |
| OEOri Enterprises LLC | Price | UT | — | ◇ UNVERIFIED |
| OEOri Enterprises LLC | Wellington | UT | — | ◇ UNVERIFIED |
| OEOriginal Exhaust Manufacturers INC | Hopkinsville | KY | — | ◇ UNVERIFIED |
| OSOrin Screws Products | Van Nuys | CA | — | ◇ UNVERIFIED |
| OAOrion Asset Management Co., LLC | Akron | OH | — | ◇ UNVERIFIED |
| ODOrion Drilling Company, LLC | Corpus Christi | TX | — | ◇ UNVERIFIED |
| OIOrion Industries, INC. | Broadview Heights | OH | — | ◇ UNVERIFIED |
| OPOrion Properties Group LLC | New Prague | MN | — | ◇ UNVERIFIED |
| OIOrlando Iron Works | Paterson | NJ | — | ◇ UNVERIFIED |
| OIOrluck Industries INC | Otsego | MN | — | ◇ UNVERIFIED |
| ODOrnalux Design Company, INC. | Oakland | CA | — | ◇ UNVERIFIED |
| ODOrnamental Design Inc | Tampa | FL | — | ◇ UNVERIFIED |
| OIOrnamental Iron Concept,bartolome Fluxa | Van Nuys | CA | — | ◇ UNVERIFIED |
| OIOrnamental Ironworks | Los Angeles | CA | — | ◇ UNVERIFIED |
| OCOrrbilt Compressors, INC. | Atlanta | GA | — | ◇ UNVERIFIED |
| OCOsage Canoes LLC | Lebanon | MO | — | ◇ UNVERIFIED |
| OWOsborne Welding, INC. | Hampton | VA | — | ◇ UNVERIFIED |
| OGOsborn General Engineering and Construction INC | Auburn | CA | — | ◇ UNVERIFIED |
| ODOscar Diaz Rivera | San Juan | PR | — | ◇ UNVERIFIED |
| OMOscar Macias and Sandra L. Macias | Gilroy | CA | — | ◇ UNVERIFIED |
| OIOseda Industries Corporation | Corona | CA | — | ◇ UNVERIFIED |
| OAOshkosh Aerotech - Jetway Systems | Ogden | UT | — | ◇ UNVERIFIED |
| OCOshkosh Corporation | Orrville | OH | — | ◇ UNVERIFIED |
| OMO&S Machine Shop, LLC | Latrobe | PA | — | ◇ UNVERIFIED |
| OIOssi's Iron Works | Las Vegas | NV | — | ◇ UNVERIFIED |
| OOOsuna Ornamental LLC | Miami | FL | — | ◇ UNVERIFIED |
| OCOsynergy Company, LLC | Edinburg | TX | — | ◇ UNVERIFIED |
| OBOttenbergs Barks | Washington | DC | — | ◇ UNVERIFIED |
| ONOur Next Energy | Torrance | CA | — | ◇ UNVERIFIED |
| OIOutlaw Industries, LLC | Clinton | LA | — | ◇ UNVERIFIED |
| OTOutlook Tool, Inc. | Dayton | OH | — | ◇ UNVERIFIED |
| OTOutlook Tool, Inc. | Dayton | OH | — | ◇ UNVERIFIED |
| OUOver Under Real Estate, LLC | Riverton | NJ | — | ◇ UNVERIFIED |
