Of course, I am speaking about ... Roxxon
It is only a juridical person and the owners & CEO have often changed but, no matter what, Roxxon is one of the recurring adversaries of Tony Stark & Iron Man.
Some theories even imply that the corporation might have killed Howard & Maria Stark.
I think Roxxon like Hammer make perfect enemies of Stark.
They are the dark side and truthfully more realistic real-world evil empires as opposed to Starks empire of companies being of the most noble bent.
Now I know Mandarin would say this is boring and all corporate intrigue...but if you present it more like empires and delve deeply into the people it affects and so on I see some great stories that could be told. Don't focus on all the board meetings...focus on the destruction and world dominating plots of Roxxon and Hammer...and Tony fighting them behind the scenes or in the public light with his technical genius + his corporate assets which include a star supporting cast like Dave and Bob had for us.