Vault-Tec Corporation

Vault-Tec is the corporation that was contracted by the United States Government before The Great War to design and produce the Vault system, dubbed Project Safehouse.

The first demonstration Vault was constructed beneath Los Angeles. It's designed deviated from the regular Vault design (for example, it had one storeroom for both arms and equipment, instead of separate storages or a much larger control room without a security outpost). After initial trials, construction of 122 vaults was put in motion.

The nuclear war shelters weren't its only area of work, as Vault-Tec released several other handbooks (such as "Coping with Mr. Virus" or "How to Cook a Rat") concerning survival during and after other disasters, with the Vault Dweller's Survival Guide being only one of many.

However, the Vaults weren't intended for saving the citizens of the United States. With a population of almost 400 million by 2077, the U.S. would need over 400,000 Vaults, and Vault-Tec was commissioned to build only 122 such Vaults. The real reason for these Vaults was to study pre-selected segments of the population to see how they react to the stresses of isolationism and how successfully they re-colonize after the Vault opens.

Future-Tec, a division of Vault-Tec, developed the G.E.C.K., the Garden of Eden Creation Kit for use by vault residents.

Like many major military contractors, as Vault-Tec grew in finances and responsibility, it began to develop highly experimental and secure technologies. In time, Vault-Tec was so thoroughly integrated with top-secret military research, it was practically a division of the U.S. government … almost. The company still retained some elements of privatization. So the principals of Vault-Tec - executives, scientists, and so on - had to be aware of the true function of the Vaults, and they had access to the technology. They were the developers. Regardless of the U.S. government's directives, Vault-Tec was not going to submit to a lottery and live underground with a bunch of human cattle in facilities that were intentionally defective. Thus Vault-Tec created their own facilities, removed from the larger Vault network - and kept secret from the U.S. government.

Vault-Tec didn't stop there. These secret, private installations were used to research the latest vault mechanisms as well as technologies that would benefit mankind in a post-nuclear environment. This, of course, included some extensive research with FEV.

No one can say for certain how Vault-Tec obtained FEV. Some think they had it all along, gaining it in a deal with the government, others think it was stolen from the government while VT was repairing one of the more guarded vaults.

Inconsistencies

 * The company is sometimes referenced as Vault-Tek.
 * While the first paragraph of Fallout: Brotherhood of Steel backstory for Vault-Tec sounds reasonable, the part about the company acquiring FEV does not fit into the Fallout canon.

Note

 * There must be some truth to Vault-Tec acquiring FEV due to Vault-Tec's experiments with it in Vault 87. Although this assumes events in Fallout 3 to be canon.
 * Or you could consider that Vault-Tec built Vault 87 not knowing about the experiment, and the scientists that used the FEV were from the enclave, so Vault-Tec could be innocent, and the enclave acquired the FEV, not Vault-Tec, making the intro for Fallout: Brotherhood of Steel non-canon again.

Appearances in games
Vault-Tec Vaults and other technology appear in all Fallout games.

Krypt-Tech Vault-Tec