A balance transfer to a new card with a 0% introductory APR can affect your credit score in which way?

Opening a new balance transfer card triggers a hard inquiry and lowers your average account age, both of which can temporarily reduce your score. Additionally, if the transferred balance is large relative to the new card's limit, the utilization on that individual card may be high, which can hurt your score even if overall utilization stays the same. The long-term credit impact depends entirely on whether you actually pay down the balance during the promotional period rather than just moving debt around.