Tax return information is private by law. If you are claimed by someone else, the IRS may contact you to resolve it, and you may be asked for proof that you aren't a dependent, but they won't tell you who did claim you. Likewise, if you claim someone else as a dependent, the IRS does not notify that person unless there is some kind of discrepancy, such as someone else claimed them or they said they were not a dependent. As before, the IRS will investigate and may ask the person to confirm their status but they won't tell the person who claimed them. (The person might be able to guess, of course.)
