When to Pay Capital Gains Tax in Sri Lanka

Most people selling land, a building, or shares in a private company focus on getting the deal closed. The deadline that catches them out comes after the money has already landed in their account. Capital gains tax in Sri Lanka runs on its own clock, separate from your annual return, and that clock is shorter than you'd expect.

This article is about the timing. Not how to work out the gain (we cover that in detail in our capital gains tax guide), but when the return and the payment are actually due, when the countdown starts, and what it costs you if you miss it.

When is capital gains tax due after a sale in Sri Lanka?

Here's the rule that matters. When you realize an investment asset, you must file a Capital Gains Tax Return within 30 days after the end of the calendar month in which the sale happened. The tax is payable on that same date.

Two sections set this. Section 93(3) fixes the filing deadline for any realization on or after April 1, 2021. Section 82(2)(c)(i) makes the payment due on the date the return is due. So filing and paying land on the same day.

The "end of the calendar month" part trips people up, so look closely at how the count works:

Notice that a sale early in the month gives you almost seven weeks, while a sale on the last day of the month gives you barely 30 days. The deadline doesn't care which. It always counts from month-end.

When exactly does the payment clock start?

The countdown begins on the date of realization. Under Section 39, you realize an asset when you "part with ownership" of it. That sounds simple, but the exact date depends on what you sold.

• Land or a building. Ownership passes when the transfer deed is executed, not when you signed an agreement to sell. An agreement to sell on its own doesn't transfer ownership, so the deed date is the date that starts your clock.
• Shares. The disposal date, the day you transfer the shares to the buyer.
• Other assets. The day you part with ownership, whether by sale, exchange, gift, or transfer.

This distinction matters more than it looks. If you sign a sale agreement in one month and the deed is executed the next, it's the deed month that sets your deadline. Get that wrong and you could start counting from the wrong month-end.

Does the same deadline apply when I sell shares?

Yes, with one big exception. Whether a share sale attracts capital gains tax at all depends on where the shares are listed.

• Listed shares. Gains on shares quoted on the Colombo Stock Exchange (or another exchange licensed by the SEC of Sri Lanka) are exempt, under paragraph (h) of the Third Schedule. No tax, no CGT return.
• Unlisted or private company shares. Gains are taxable, and the same Section 93(3) deadline applies. Sell unlisted shares on August 10 and your return and payment are due by September 30, exactly like a property sale.

So a portfolio of CSE-listed stock generates no CGT deadlines at all. But the moment you sell a stake in a private company, a friend's startup, or a family business, you're back on the 30-day-after-month-end clock. For the wider picture on how dividends, interest, and gains fit together, see our guide on how investment income is taxed in Sri Lanka.

What do I file and pay, and is it part of my quarterly payments?

A common assumption is that a capital gain gets swept into your quarterly tax installments or your year-end return. It doesn't.

Capital gains tax sits outside both. Your quarterly tax payments cover employment, business, and investment income, and they carry on unchanged when you sell an asset. The gain is settled separately through its own CGT return within the 30-day window.

That means if you sell a property and also earn a salary or run a business, you'll end up filing two separate things for that year:

1. A Capital Gains Tax Return within 30 days after the month of the sale, with the 15% tax paid at the same time.
2. Your normal annual income tax return for the year of assessment, covering everything else.

The 15% rate is the current one, effective from June 3, 2026 under the Inland Revenue (Amendment) Act, No. 11 of 2026. Disposals before that date were taxed at 10%. The mechanics of working out the gain, the cost base, and the exemptions are all in the capital gains tax guide, so this article won't repeat them.

What happens if I miss the capital gains tax deadline?

Missing the window is expensive, and two separate charges apply at once.

Late-payment interest, under Section 157. Interest runs at 1.5% per month (or part of a month) on the unpaid tax, counted from the original due date until you actually pay. It keeps accruing even if you've asked for more time.

Late-filing penalty, under Section 178. This is the greater of two calculations:

• 5% of the tax owing, plus 1% of the tax for each month the return is late, or
• Rs. 50,000, plus Rs. 10,000 for each month the return is late.

Whichever is larger applies, and the total is capped at Rs. 400,000 per return.

For more on how the 2026 amendments reshaped penalties and interest across the board, see our breakdown of the 2026 IRA penalty changes.

How is this different from my annual tax return?

The simplest way to hold the two apart is this: your annual return is periodic, and capital gains tax is transactional.

You can owe both in the same year and on completely different dates. Selling a plot of land in June doesn't move your November quarterly installment, and it doesn't wait for your annual return the following year. It has its own June-month-end deadline and is done.

How do I make sure I don't miss the window?

The trap with capital gains tax isn't the calculation. It's that the deadline arrives weeks after the sale, once you've moved on and the paperwork is filed away. By the time anyone mentions a CGT return, half the window is often already gone.

The fix is to lock the deadline in on the day the deal closes. Pull the execution date off the deed, count to the end of that month, add 30 days, and put that date somewhere you'll see it. Keep the deed, the cost receipts, and the selling-cost invoices together so the return itself takes minutes, not days.

Selling an asset is rare enough that the rules never feel familiar. But the timing is the one part you can't afford to improvise. Fix the deadline the day you sell, keep your paperwork in one place, and the CGT return becomes a quick formality instead of a costly scramble.