Another case where a computer manufacturer ended up designing their own CPUs was the UK company Acorn, developer of the BBC computers. A couple of existing in-house staff, one the author of BBC BASIC, sat down and came up with the first RISC design intended for home computers; the Acorn RISC Machine, now known as ARM.
After a while, Apple came on board and the technology was spun out of Acorn into the new Advance RISC Machines Ltd. with Apple as a shareholder.