It appears that this 1099B entry is related to the acquisition of Banco Popular by Banco Santander in July/August 2017. The acquisition was an all stock purchase with new stock being issued by Banco Santander through a tender offer. The tender for new stock closed on 07/20/2017; on 08/03/2017 my TD Ameritrade account is credited with a "Qualified Dividend" of 248.63 which, after subtracting for an ADR fee of 23.06, comes to 225.57. I did not participate in the tender offer, so I am assuming that this non-regular dividend had something to do with adjusting stock values to account for the tender offering. I am inclined now to treat this as a return on capital. What do you think?
