Xycorp was founded in the year 2080 by Jic Xyk. A decendent, Kyp Xyk, already one of the richest men on Earth, invested heavily in the research leading to the Thayeson Reactor Mark I. He used the profits from Thayeson’s success to join the Great Exodus and managed a foothold in space before his own health and company politics froze the corporation and it subsequently missed out on the System Rush.
Xycorp managed to ride the coattails of Thayeson Enterprises off and on over the next centuries, depending mostly on how well Xyk toed the line for Thayeson. More recently the two have had legal difficulties over territory.