- O Premium Waters Acquired By DS Waters of America
- O Saw and Tool Acquired By Techniks Tool Group
- O Telhar Agro Acquired By Capital Group Private Markets
- O&3 Acquired By IMCD N.V.
- O&P Enterprises Acquired By Curbell Plastics
- O brien & Gere Acquisitions
- O Brien Acquired By AMETEK
- O Brien Custom Air Acquired By Rinaldi’s Air Conditioning Service
- O Brien Customs & Forwarding Pty Acquired By Rhenus AG KG
- O Brien s Response Management Acquired By Witt O Brien s
- O Byrne Distributing Acquired By Snyder s-Lance
- O Charley s Acquired By Fidelity National Financial
- O connell investment services Acquired By Independent Bank
- O Connors Acquired By Esken
- O'Conor Wright Wyman, Inc.
- O Currance Teleservices Acquired By Fusion BPO Services
- O Donnell Metal Deck Acquired By Slate Capital Group
- O Flaherty Holdings Acquisitions
- O Gorman & Young Acquired By Arthur J. Gallagher
- O Grady Peyton International Acquired By AMN Healthcare Services
- O'Hare Management LLC
- O Keefe Elevator Acquired By TK Elevator
- O Leary and Partners Acquired By The Shipyard
- O Malley & Kwit Acquired By Sikich
- O Malley Hansen Communications Acquisitions
- O'Melveny & Myers
- O Neal Steel Acquisitions
- O Neil Acquired By Gifford Associates Insurance Brokers
- O Neil Financial Services Agency Acquired By Brown & Brown
- O Neil Product Development Acquired By Dover
- O'Neill & Borges LLC
- O Neill Consulting Group Acquisitions
- O Neill Marketing Acquired By Senior Market Sales
- O Reilly Automotive Acquisitions
- O Reilly Media Acquisitions
- O Rourke Petroleum Acquired By Mansfield Energy
- O Shares Investments Acquired By SS&C Technologies Holdings
- O Shaughnessy Asset Management Acquired By Franklin Resources
- O'Sullivan Partners Pty Ltd.
- O-bit Telecom Acquired By Daisy Group
