Mike Muller, the co-founder and chief technology officer of ARM Holdings Plc, will retire at the end of the month.

Muller had served as ARM’s CTO for nearly 20 years. Hr was one of the founders when ARM was created in 1990. A Cambridge University alum, he also acts as a non-executive director of Cambridge Innovation Capital, which funds companies that start in the school or the “Cambridge ecosystem.”

ARM was the U.K.’s largest listed technology company, receiving royalties from companies such as Apple and Samsung Electronics, when Masayoshi Son’s SoftBank Group Corp. bought it for $32 billion in 2016. Since then, the British company added about 2,000 employees and plans a new building on the Cambridge campus.

Son has said he wants to relist ARM in the next five years and Chief Executive Officer Simon Segars said ARM is investing heavily attempting to break into high-end computing and to become central to self-driving car technology.

In 2018, ARM spend $600 million for a data analytics startup in an attempt to build out its internet-of-things division.