Any value (money, miles, points, coupon, toaster) for opening a deposit account will be reported, typically on a 1099-INT.

Likewise, value you receive for a referral will be reported, typically on a 1099-MISC.

On the other hand, value you receive for opening a credit card is not reported because it is treated as a partial refund of the spend required to earn the bonus.

Upgrade bonuses usually have an attached spending requirement, so there should be nothing to report, but if you receive a "no spend" bonus it might be reported the same as a referral bonus.

Card issuers do make mistakes. The 1099 form may have a code or partial account number to help you identify the source. You may not recognize it if the account has been closed, or card reissued. The issuer should be able to tell you, but if you call the agent simply wants to get you off the line and may guess.

Cardholders do forget bonuses. Approach with an open mind. Did you receive a bonus for changing to paperless statements? Did you receive a bonus to compensate for an error?