Filing of Interim Corporate Income Tax Return due by September 2, 2019


A resident corporation (and a nonresident corporation having a permanent establishment in Korea) is required to pay interim corporate income tax within 2 months from the end of the first six months of each fiscal year. An Interim corporate income tax return must also be filed along with the tax payment. A corporation with the December 31 calendar fiscal year-end must file 2019 interim corporate income tax return no later than September 2, 2019 (as the original due date of August 31, 2019 falls on weekend this year).

The interim corporate income tax return can be filed using either (i) the 1/2 method (that is, paying 1/2 of the corporate tax paid in the prior year) or (ii) the book-closing method (by closing the books of accounts of the corporation for the first six-month period and calculate interim corporate tax amount based on the financial results of such first six months). When a corporation had not paid corporate income taxes in the prior year due to tax loss or having no taxable income, only the option (ii) above should be applied.

The calculation formula of interim corporate income tax by using the book-closing method is as follows:

Tax payable = [taxable income for interim period12/6] tax rates 6/12

- (tax exemption/withholding taxes paid and taxes assessed for the interim period)

If the interim corporate income tax payable exceeds Won 10 million, such tax can be paid in 2 installments as below. The second installment payment is due within 1 month from the end of the filing due date (2 months in the case of small and medium corporations (defined)).

If interim income tax payable is:

Installment payments can be

broken down as below:

Over Won 10 million

~ up to 20 million

1st installment

10 million

2nd installment

Excess over 10 million

Over Won 20 million

1st installment

50% or more of tax payable

2nd installment

Remaining 50% balance

- 1st installment is due together with filing of the interim tax return within 2 months from the end of the first 6 months (i.e., August 31 for the calendar fiscal year-end).

- 2nd installment is due within 1 month from the end of the filing due date (i.e., September 30 for the calendar fiscal year-end).

Unlike the annual corporate income tax return, there is no additional local (provincial) income tax payable on interim corporate income tax liability.