Renraku is a good guess. They already do a lot of data/software work, so there's that. Plus, they're the least objectionable of the other choices. Going down the others of the big 10 (including Spirad, since they get JRJ):
Ares - Not really known for their stellar matrix abilities. Plus, they've got bug problems, and while the general public may not know that, you can bet that the megas know, or suspect.
Saeder-Krupp - Everyone remembers how Lofwyr 'saved' the European Matrix by installing kill switches in everything that he could activate at a moment's notice. No way the megas allow SK to have that much sway. Also, Spinrad would object like hell.
Wuxing - Not enough Matrix assets to really make a play for it.
EVO - Monad and TM associations = NO
Aztechnology - Hahahaha. No. No way they put the people famous for stealing anything that isn't nailed down in charge of the Matrix. Also, Horizon would object like hell.
Horizon - No way the put the experts in subliminal messaging in charge of the Matrix. Also, Aztechnology would object like hell.
Spinrad - Too new to the club, former NeoNET assets not a recommendation, SK would object like hell.
Shiawase - Too out in the open for them, and their matrix resources aren't something they're really known for being a leader in.
MCT - Their tech is top of the line, but SK will object like hell, since they knocked them off as #1 in the world. They're #1, so the others won't be keen on giving anything more to them, either.
Of all the Big 10, Renraku is the only one with the tech, expertise, and lack of major objectionable material.