> what qualifies as a lions share?

If you follow Phaedrus's telling[0], introduced as "Partnership with the mighty is never trustworthy" -- all of it:

"I take the first portion because of my title, since I am addressed as king; the second portion you will assign to me, since I’m your partner; then because I am the stronger, the third will follow me; and an accident will happen to anyone who touches the fourth."

Other versions from around the world typically have the lion taking a majority of whatever is being divided, and whenever possible, everything.

--- [0] https://en.wikipedia.org/wiki/Lion%27s_share#The_Phaedrus_ve...

The better question, in my opinion, is what qualifies as a "CEO?" The article makes it clear that they just cherry-picked the top paid 350 CEOs in the country. But there's nearly a quarter million CEOs in the US.