JRJ was big, but not big enough that a corporate shark like Villiers couldn't get an angle and take it over. (Out of game, it is likely a flipped R.J. Reynolds (RJR), which is one of, if not the, biggest tobacco companies out there, and was a big deal in the 80's.) Like Mirikon said, it's likely essentially a holding company -- think Berkshire Hathaway -- which was, at the time, considered one of the biggest, or at least one of the most influential, corporations in the world.
After Villiers got a hold of it, he realized that keeping it instead of shredding it was the way to go, and so he was in the driver's seat when the Corporate Court first got formed. Snapping up Matrix Systems of Boston got him the leverage to turn to Fuchi's other two leaders (Nakatomi and Yamana) and offer a) first crack at cyberdecks, and b) an auto-in on the Corporate Court (because of JRJ's golden ticket) if they'd cut him in for 1/3 of the company. Nakatomi (who had been originally white-knighted by Yamana, but which had turned into a quasi-takeover-turned-merger) refused ... and got whacked three days later by his limo driver. His son 'saw the light' and agreed, but never forgot.
JRJ, however, remained the golden ticket, and when Richie Rich (Villiers) finally decided 'screw these guys, I'm goin' home', he quietly sold himself JRJ out from under the other two and Novatech was born. Merge with Erika and Transys because of Art Dankwalther hijinks, and there you go.
I have not, alas, kept up with the very latest corporate hijinks, so while I understand NeoNET has collapsed, I don't know the details, so ...