My aversion to it is it's utterly unnecessary, so why do they need it and why are they refusing to tell me the reason? Thats my aversion. I'm not a fan of signing a form and sending it out into god knows where so anyone who can get their hands on it can access that info.

Never before has a credit card requested it. Just because it seems innocent enough is not reason to comply.

To try and answer other questions - I did open two chase cards in the last 4 months, but one was a business card in my business' name. That card, they are not requiring any information.

Let me reiterate here - they are not attempting to validate anything except the information they already have. Which tells me something else is going on. And when I ask them, the question is evaded, not answered.

No one needs a W9 to "update their system" when no one else does it.