On 1 January 2026, the most far-reaching changes to Sweden's 3:12 rules in decades came into force. What often gets overlooked in the discussion: everything starts in the share register.
On 1 January 2026, the most far-reaching changes to Sweden's 3:12 rules in decades came into force. For active owners of closely held companies, this brings new conditions – both opportunities and pitfalls. One thing that often gets lost in the discussion around the new rules is that everything begins in the same place: the share register.
Previously, there were two methods for calculating the threshold amount (gränsbelopp) – the simplified rule and the main rule. From income year 2026, these are replaced by a single unified model with three components: a base amount, a salary-based allowance, and an interest-based allowance.
The base amount equals four income base amounts per year, which for 2026 corresponds to SEK 322,400. The amount is distributed proportionally across your shares – and if you hold shares in more than one closely held company, the base amount must be split between them. It is no longer possible to choose which company to apply it to, as was previously the case with the simplified rule.
The salary-based allowance is calculated as 50 percent of the wage basis after a standard deduction of SEK 644,800. The mandatory salary withdrawal requirement has been abolished, but a salary must still be paid to generate any salary-based allowance at all.
The threshold amount is calculated based on your ownership share at the start of the tax year – that is, 1 January 2026. It is therefore the ownership structure recorded in the share register at that precise date that determines how much room you have for low-taxed dividends.
That sounds straightforward, but in practice this is where things often go wrong. New share issues, transfers, and option programmes completed during 2025 but not correctly recorded in the share register can result in inaccurate ownership figures – which in turn leads to an incorrect threshold amount and an incorrectly completed K10 form.
It is important to keep the two sets of rules separate.
For the tax return you file in spring 2026 – covering income year 2025 – the old rules still apply in full. The K10 form is submitted this year primarily if dividends have been received, or if you wish to preserve and accumulate allowance space for the future. The deadline is 2 May 2026.
From income year 2026 onwards (K10 filed in spring 2027), the new rules apply. From then on, a K10 must be submitted every year as long as you hold qualified shares – regardless of whether any dividend has been paid. Accumulated dividend allowance will also no longer be indexed forward automatically between years.
This means every year now carries more weight than before – and a missed or incorrectly recorded change in ownership can have consequences for your tax return for several years to come.
Reporting obligations for dividends (KU31) have existed for a long time and are not new. What changes under the 2026 legislation is that closely held companies are now subject to an expanded reporting obligation – information must be submitted on an ongoing basis about who the owners are, the number of shares held, and any changes in ownership. According to the legislative proposals, the purpose is to enable more automated processing by the Swedish Tax Agency and to strengthen its audit capabilities.
The practical consequence is that a significantly more complete register of owners in closely held companies is now being built up. If a company's own records of its ownership structure do not align with what the Tax Agency receives through reporting obligations, questions arise – and the risk of enquiries and deeper scrutiny increases.
It is not the auditor or the accountant who is responsible for keeping the share register accurate. That responsibility rests with the board of directors. And a company whose share register does not reflect the actual ownership structure lacks the very foundation on which the entire tax calculation rests.
As the regulatory framework around closely held companies tightens and the expanded reporting obligations make ownership structures more transparent, there is good reason to ensure the share register is kept up to date – not once a year, but continuously.
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Questions about keeping your share register in order? Get in touch with us at eAktiebok.