I can't find the exact sources I read previously, but Googling it I see some here:
https://www.investopedia.com/ask/answers/110614/are-credit-card-rewards-considered-taxable-income-ir...
- "Rewards provided as an incentive just for opening an account (without you spending any money) could be considered taxable income."
https://www.cnbc.com/select/are-credit-card-rewards-taxable/
- " If you earned $200 cash back after you spent $500 on purchases in your first three months from opening a Chase Freedom® account, or if you earned 2% cash back (1% cash back when you bought, plus al 1% when you paid your card bill) on purchases you made in 2019 with the Citi® Double Cash Card , none of those rewards are taxable because you were required to spend money to receive them. (see rates and fees.)
Most credit card rewards are earned once you actually start using the card. There are only a few cards that award a welcome bonus automatically after account approval with no spending required.
If you didn’t have to charge purchases on your card in order to receive the welcome bonus, the value of that reward is considered taxable income. For example, you opened a new Prime Visa account and received a $100 Amazon.com gift card.
“The only time that credit card rewards are taxable is when you do nothing in exchange for the reward, i.e. you get 60,000 miles for signing up for a credit card, with no minimum spending,” Rossman says."
https://money.usnews.com/credit-cards/articles/are-credit-card-rewards-taxable
- "Credit Card Sign-Up Bonuses
When it comes to sign-up bonuses, things get a little murkier. Depending on how you earned the bonus, the points may or may not be taxable.
Let's say you opened a credit card that offered a 50,000-point bonus for meeting a spending requirement of $3,000 within the first three months of opening the account. If you met the requirement and earned the bonus, you wouldn't have to report the points as income because you spent your own money to get the bonus.
Here's where it can get sticky: If you didn't have to meet a spending threshold and you were awarded the points for simply opening an account, the value of those points would be considered taxable income by the IRS. From the perspective of the IRS, you didn't earn the bonus, so it's considered a gift."
