You know what, beatle is right, I'm wrong. Not sure when or how I developed the misconception, but I'm sorry for speaking outside my area of expertise and blowing it.
Sorry, I don't know. I think that's the case for all public companies in the US, at least (I don't know if it applies to limited parterships, private corporations, s-corporations, etc). I searched to confirm CEOs were not necessarily fiduciaries before I posted, and I did see that officers could be fiduciaries (eg, for internally managed pension funds - though it didn't have to be the CEO).
