Solidarity tax (ST) has been charged for several years on incomes exceeding the annual threshold of €62,800 set by the Cabinet of Ministers for mandatory national social insurance (NSI) contributions last year and this year. As the 2019 filing season has begun, this article serves as a reminder that under the current rules, persons whose income went over the threshold in 2019 must file their annual income tax return between 1 April and 1 July 2020.