Full name Renraku Computer Systems. A megacorporation in the Shadowrun world that specializes in computer hardware, software and services. Their home office is in Chiba, Japan, but they have a strong presence all over the world, especially in Seattle (the focus around which the Shadowrun world was created) where they built an arcology in 2040.

renraku is a Japanese word that's usually used in the form renraku suru which means "to contact", so it's quite well-chosen for a company that manufactures computer (and, by extension, communication) equipment.