"Corrupting the legal system" is how Palpatine ensured Gunray never got convicted after TPM.

As the Naboo governor puts it in AOTC:

"It's outrageous. But after four trials in the Supreme Court, Nute Gunray is still the Viceroy of the Trade Federation. I fear the Senate is powerless to resolve this crisis."

And "greed" is what drives him to rule the galaxy - he wants the whole galaxy to be "owned by him" at least in the metaphorical sense.