Iberdrola pays the half-year dividend in the form of subscription rights. The booking of the subscription rights is considered an inflow for tax purposes and is therefore subject to capital gains tax. With some brokers, these subscription rights can be traded, but as far as I know, the booking is obligatory and takes place at a ratio of 60:1 https://www.iberdrola.com/shareholders-investors/shareholders/dividends-iberdrola-retribucion-flexible
