I have a dual citizenship (US and non-US), and I have never lived in the US, nor have I worked in the US, except for 4 non-consecutive months as a counselor in a summer camp.
I work in a multi-national corporation (based in the US), and my stock options are managed in the US. The investment bank there is asking all employees to file a W8-BEN or a W-9.
Am I required to file a W8-BEN or a W-9? On the one hand, I am a US citizen, on the other hand, I don't live or work in the US.