Involved in the production of Kearny-Fuchida Drives since the dawn of interstellar space travel, the O'Neil Yards orbiting Terra was one of the leading power-brokers of aerospace industry in the Inner Sphere.
Involved in the development of the first JumpShips during the early days of interstellar travel, the O'Neil Yards used their position to branch into nearly every aspect of aerospace production. By the 31st century the company owned the majority stake of the Titan Yards complex, the Phobos Materials Complex, NETC's Orbital Facility, as well as number of large scale projects across the Lyran Alliance and Federated Suns. Despite their massive influence in the aerospace community, over the centuries O'Neil preferred to let the industry drive itself rather than seek to direct and control it, also maintaining a strict policy of neutrality with all Inner Sphere factions. Taking great pride its neutrality, the company responded harshly to any that endangered it, most notably in 3059 when the entire Panpour office was terminated after O'Neil's internal investigation saw several cases of corporate malfeasance. 
Its storied yards in the Terran system continued to function during the worst technological decline of the Succession Wars, O'Neil fulfilled contracts to supply and maintain civilian Jump and DropShips for ComStar's internal and Explorer Corps fleets, while the Word of Blake increasingly requesting military craft such as the Manei Domini's Tiamat Pocket WarShip and its Caspar II Drone counterpart. 
Despite its "factional neutrality", much like the facilities around Titan, the O'Neil Yards suffered horrific damage during Stone's Coalition's liberation of the yards during Operation SCOUR.   Due to the vital role of the yards to civilian as well as military production, the newborn Republic of the Sphere expended considerable effort to rebuild and restore the Terran based shipyards, even as they were assisted with the arrival of the Newgrange-class RoSS Mercy. 
Most notably and worryingly for the newly formed Republic Armed Forces black water navy was the complete loss of O'Neil's WarShip Transit Drive manufacturing facilities. Estimates indicated it would take over a decade to restore them and then only at cost of rebuilding elsewhere, pushing the RAF high command to look towards Pocket WarShips to fill the gap instead. Despite the stigma of Tiamat drones brutal actions during the liberation of Terra, the RAF took the pragmatic choice to repair the DropShip's damaged production lines to revive the original manned version to bolster its fleet. Restoration of production lines for other craft, such as the Achilles-class, continued at a much slower pace. 
O'Neil Yards has manufacturing centers on the following planets:
|Components produced on Terra:|
|Kearny-Fuchida Drive - Jumpships|
|? (for Magellan)||Magellan|
- Masters and Minions: The StarCorps Dossiers, p. 219, "O'Neil Yards Profile"
- Technical Readout: 3057 Revised, p. 98, "Manufacturing Note"
- Technical Readout: 3085 Supplemental, p. 38 "Dragau and Tiamat DropSpShips"
- Jihad Hot Spot: Terra p. 134 "Corporate Chaos"
- Jihad Hot Spot: Terra p. 175 "Touring Terra"
- Technical Readout: 3085 Supplemental, p. 40 "Newgrange III YardShip"