
Interestingly, Skynet was a real UK military communication satellite system in the past.
On the other hand, Intel was a fictional rogue electronics corporation, which stole the design for a computer, built by a UK government establishment, to a design received by Jodrell Bank radio telescope from the Andromeda nebula. See Fred Hoyle's "A for Andromeda".
The names of other rogue corporations come to mind, but you have to go a long way to beat the Honourable East India Company, which took over India, using its own private army.