Zirunkariish was . . . founded by the noble Vilani family of Shiishuginsa in -425.
Delgado was . . . Founded in 997.
General is a major heavy industry company known for inexpensive products of fair to adequate quality. The company was formed by merger of a number of smaller manufacturing concerns shortly after the end of the Civil War, in the period 620 to 622.
Instellarms is a specialty supplier of military goods . . . Founded in 626, shortly after the end of the Civil War.
Hortalez is the dominant insurance and financial services company within the Imperium.. . . Founded in 221 by Lucienne Hortalez, and capitalized from family funds.
Sternmetal Horizons traces its origins to a merger (or hostile takeover) of Vilani starship construction companies by the Terran naval contractor Sternmetal in the early days of the post-First Empire occupation. The result survived the Long Night to become a major supplier to Imperial and planetary navies.
GSbAG is a major shipbuilder providing a range of services from construction to ship support, maintenance, and upgrades. The company manages starports through the Imperium. Founded in -2438 from a consortium of old Terran manufacturing firms (this history is disputed).
ImperialLines is a major interstellar shipping firm (and rival to Tukera Lines). Despite covering most of the entire Imperium, its assets are not large enough that it is considered a megacorporation. Formed in the decades after the Civil War with major investments from the Imperial family.
LSP Ling Standard Products pursues industrial production and natural resource exploitation with a series of vertically integrated channels which dominate the markets in specific systems and regions. Founded by the legendary Captain John Meyers during The Rule of Man.