Converting a sole trader business into a limited company (sp. z o.o.): when it is worth it and how to do it
Converting a sole proprietor into a capital company under Article 584 of the Commercial Companies Code (KSH). Tax consequences, continuity of contracts, licences, and the alternative of a contribution in kind.
When a sole trader business “outgrows” its one-person form, the question arises: what next? Most often the answer is conversion into a limited liability company. Since 2012 the Commercial Companies Code (KSH) has offered a clear path for this (Article 551 § 5 and Articles 584¹–584¹³ KSH): the conversion of a sole proprietor, with universal succession of assets, contracts and liabilities.
The article explains when conversion makes sense, how it works technically and what the alternatives are. Legal position as at 22 October 2026.
Two paths: conversion vs contribution in kind
For a sole trader business that wants to “turn into” a limited company (sp. z o.o.) there are two main routes:
1. Conversion under Article 551 § 5 and Articles 584¹–584¹³ KSH (universal succession)
An entrepreneur entered in the Central Register and Information on Business (CEIDG) becomes the sole shareholder of a limited company (a one-person company). The whole business, all contracts, licences and liabilities pass to the company by operation of law. This is the “cleanest” legal path.
2. A contribution in kind of the whole enterprise to a new company
You set up a new limited company and contribute your whole enterprise to it as a contribution in kind (within the meaning of Article 55¹ of the Civil Code). There is no universal succession: contracts need to be assigned, and licences usually need a separate transfer. It is cheaper and faster, but more complicated operationally.
| Parameter | Conversion | Contribution in kind | |----------|----------------|-------| | Succession of contracts | Automatic | Requires assignment | | Time | 3–6 months | 1–3 months | | Statutory auditor’s opinion | Required | Optional | | Accounting | Opening balance = the sole trader’s balance sheet | New accounting | | NIP (tax identification number) and REGON | The company gets new ones | The company gets new ones | | The sole trader’s number in the National Court Register (KRS) | CEIDG closure after the conversion | CEIDG closure in parallel |
When conversion pays off
The decision to convert is not only a tax one. We take into account:
Arguments for conversion
- Limited liability: a shareholder in a limited company is not liable with their private assets (except for tax arrears and contributions to the Social Insurance Institution (ZUS) in some cases)
- Tax optimisation: Estonian CIT allows tax to be deferred until a dividend is paid out
- Easier to bring in a partner or investor: shares in a limited company are easy to transfer
- A higher valuation of the business on sale: a company with an operating history is easier to sell
- A professional image: “sp. z o.o.” inspires more trust in B2B
Arguments against
- Full accounting is compulsory: the Accounting Act instead of the simplified PKPiR
- Higher costs of service: accounting, audit, returns
- Full ZUS for the shareholder: a one-person limited company = ZUS contributions like a sole trader business, without reliefs
- Double taxation: CIT + PIT on the dividend (26.29% effectively in total)
- Restrictions on using the company’s funds: the shareholder cannot “take from the till”
Estonian CIT: a game changer
Estonian CIT (strictly speaking: a lump-sum tax on company income) is available to limited companies and gives the option of deferring tax until the moment profit is paid out. For companies that invest actively, this is a real benefit.
Estonian CIT: the company pays the lump-sum tax only when profit is paid out: 10% (a small taxpayer and a taxpayer starting a business) or 20% (others). The shareholder pays 19% PIT on the dividend, reduced by 90% (small taxpayer) or 70% (others) of the lump-sum tax attributable to their share. Only individuals can be shareholders.
We describe the conditions for entry in the article Estonian CIT 2026.
The conversion procedure, step by step
- Profitability analysis: at least 2 scenarios
- Conversion plan: a document containing the valuation of the assets and a draft of the new company’s articles of association
- Gathering the assets: the sole trader’s balance sheet as at a specified date, valuation of the items
- Statutory auditor’s opinion: required for conversion (for a contribution in kind, only if the cash contribution is below the value of the item contributed)
- Declaration of conversion: in the form of a notarial deed
- Entry in the KRS: the converted entrepreneur becomes the sole shareholder of the limited company
- Closure of CEIDG: automatic after the entry in the KRS
- Announcement in the Court and Commercial Gazette (MSiG): obligatory after registration
- Updating contracts: most pass by succession, but some business partners require an annex
- New accounting: full, from the date of conversion
The whole process usually takes 3–6 months from the decision to the entry in the KRS.
Tax consequences
At the moment of conversion
- No tax on income: the conversion does not generate income to be taxed (tax neutrality)
- VAT unchanged: succession also applies to VAT, and the company continues the invoice numbers
- Depreciation of assets: the company continues depreciation from the book value
During the limited company’s operation
- CIT on income: 9% for small companies (< EUR 2 million of revenue) or 19% for the others
- PIT on payments: dividend 19%, pay from an employment relationship or contract under the scale
- ZUS for a one-person shareholder: full (pension, disability, accident, sickness, health)
Alternatives to consider
If income is growing but full conversion into a limited company seems too big a step:
- A limited partnership: with the sole trader as the limited partner, easier succession
- A limited company with two shareholders: avoids the ZUS trap of the one-person shareholder
- A simple joint-stock company (PSA): for start-ups with expansion potential
- A family foundation + a limited company: for succession planning and asset protection
Summary
Converting a sole trader business into a limited company is a strategic decision, not only a tax one. Done well, it gives limited liability, a better path for growth and tax optimisation (especially with Estonian CIT). Done badly, it generates extra costs and complications with no real benefit. At Profais we prepare an initial analysis for clients. We compare 3 scenarios (staying as a sole trader, conversion, a limited partnership) using real numbers from the books. We are an accounting firm, not a tax adviser. Tax advice and opinions that go beyond day-to-day accounting are provided by tax advisers, and corporate matters (the articles of association, the KRS) by a notary and a legal adviser (in line with the Tax Advisory Act). See our full accounting service and the article on the family foundation.
Sources: Commercial Companies Code (Article 551 § 5, Articles 584¹–584¹³), the PIT and CIT Acts, biznes.gov.pl, krs.ms.gov.pl.