As per the repetitive Article 120 of Income Tax Law and Article 32 of Corporation Tax Law, advance tax returns are submitted to the affiliated tax office until the end of the 14th day in the second month following the concerning quarterly period and accrued taxes are paid until the end of the 17th day of the same month.
Accordingly, the advance tax returns concerning the period of Jan-Dec/2018 were required to be submitted until 14 Feb 2018 and accrued taxes had to be paid until the end of 18 Feb 2018 Monday (since 17 Feb corresponds to the weekend).
Through the Tax Procedures Law Circular no.111 published on 13 Feb 2019 by the Revenue Administration on its official web-site, the submission date of advance tax returns concerning the period of Jan-Dec/2018 for income and corporate taxpayers has been extended until the end of 18 Feb 2018 Monday.
The aforementioned extension also involves the taxpayers with special accounting period whose submission deadline concerning the relevant advance tax period is the end of 14 Feb 2019.
Taxes accrued over the tax return are required to be paid until the same date (18 Feb 2019).