How the form changes and what you need to know. The K10 form is the real "engine" in the 3:12 system. This is where you calculate the year's dividend allowance and report dividends or sales of qualified shares.
4 min readThis means the 2025 tax return (for 2024) and the 2026 tax return (for 2025) are completed under the old rules.
K10 is used to:
From 2026 you must file K10 even if you do not take dividends or do not have any saved allowance to report.
Because the Swedish Tax Agency wants continuous oversight of qualified shares, even in years when nothing happens.
In K10, the calculation will follow the new "single-model rule". You add together three parts:
Indexation of the cost base is only applied to the portion that exceeds SEK 100,000.
In K10, saved allowance has previously been increased year by year through an "interest" uplift. That element disappears.
The waiting period is shortened to 4 years for new waiting periods that start in 2026 or later.
Once shares become non-qualified, K10 is no longer filed, and taxation is instead handled as capital income under ordinary rules. But if you are already in a waiting period before 2026, the 5-year rule still applies.
It depends. Since the salary base for 2026 is built on 2025 salaries and the ownership position as of 1 January 2026, planning your salary/ownership may affect future dividend allowance.
You no longer get two standard allowances. The base amount must be split between companies, and K10 needs to reflect that.
That can be a relevant consideration since the indexation is removed. But whether it is beneficial for you depends on the full picture (salary, dividends now vs later, possible future sale, etc.).
For dividends/disposals during 2026. The first K10 under the new rules is filed in spring 2027 (income year 2026).
Yes. If you have qualified shares, you must file K10 every year from the 2026 rules onwards.
You calculate the dividend allowance using one shared model: base amount + salary-based allowance (after the 8-IBB deduction) + capital component.
The standard/base amount must be allocated between companies. You can no longer apply the "full standard allowance" in each company.
Yes, but without annual indexation. You carry forward the same nominal amount.
No. When shares are no longer qualified, they are reported as ordinary capital shares and K10 is not needed.
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