Starting a business in Finland comes with a clear first step: obtaining a Finnish Business ID, known locally as the Y-tunnus. Whether setting up a limited liability company, operating as a sole trader, or registering a branch of a foreign company, this identifier is the foundation of every legitimate business operation in the country. Understanding what it is, how to get one, and where it applies can save considerable time and frustration when navigating Finnish company registration.
Finland has a well-structured and largely digital business registration system, making the process more accessible than in many other countries. That said, there are still important details to get right from the start. This guide walks through everything needed to apply for a Y-tunnus and use it correctly once registered.
Who needs a Finnish Business ID
Almost every entity conducting business activity in Finland requires a Y-tunnus. This applies to a wide range of business structures, and understanding which category applies is the first step toward registration.
Under Finnish law, the following entities must register for a business ID:
- Limited liability companies (Osakeyhtiö, Oy)
- General and limited partnerships (Avoin yhtiö, Kommandiittiyhtiö)
- Sole traders (Toiminimi) who operate in a trade, craft, or service sector
- Cooperative societies (Osuuskunta)
- Associations and foundations with business activity
- Foreign companies operating a branch in Finland
Private individuals who occasionally sell goods or services may not always need to register, but once business activity becomes regular or professional in nature, registration is typically required. The Finnish Trade Register Act (Kaupparekisterilaki 129/1979) and the Act on the Business Information System (Laki yritys- ja yhteisötietojärjestelmästä 244/2001) together define who is obligated to register and under what conditions.
What the Y-tunnus looks like and what it represents
The Y-tunnus is a seven-digit number followed by a hyphen and a single check digit, formatted as XXXXXXX-X. This structure is standardised across all business types in Finland and is assigned permanently to the entity upon registration.
The identifier is not just an administrative label. It serves as the unique anchor for all public information about a company in the Finnish Business Information System (YTJ), which is jointly maintained by the Finnish Patent and Registration Office (PRH) and the Finnish Tax Administration (Verohallinto). Through YTJ, anyone can look up a company’s registration status, business address, industry classification, and key contact details using nothing more than the Y-tunnus.
It is also worth noting that the Y-tunnus is separate from the VAT number, though the two are closely linked. When a Finnish company registers for VAT, the VAT number is simply the Y-tunnus prefixed with “FI” and without the hyphen. For example, a company with the Y-tunnus 1234567-8 would have the VAT number FI12345678. This makes cross-referencing between the two systems straightforward.
How to apply for a Y-tunnus in Finland
Applying for a business ID in Finland is handled through the Business Information System portal at ytj.fi, or alternatively through the PRH’s dedicated registration services. In 2026, the majority of registrations are completed fully online, though some business forms still require paper submissions in specific circumstances.
Online registration via ytj.fi
The YTJ portal allows founders to submit startup notifications electronically for most business structures. The process requires strong electronic identification, such as Finnish online banking credentials or a mobile ID. Once the notification is submitted, the PRH processes the application and issues the Y-tunnus, typically within a few business days for straightforward cases.
Registration fees
Registration fees vary depending on the business structure. As of 2026, the PRH fee for registering a private limited company (Oy) through the online service is significantly lower than the paper-based equivalent, which incentivises digital registration. Sole traders registering only with the Tax Administration pay no PRH registration fee if they are not required to enter the Trade Register.
What information is required
The startup notification typically requires the following details:
- The legal name of the business
- The chosen business structure
- The registered business address in Finland
- The main line of business (using the TOL 2008 industry classification)
- Details of founders, shareholders, or partners
- Information about the board of directors or responsible persons
- Whether the company wishes to register for VAT, as an employer, or in the prepayment register
Submitting accurate information at this stage is essential, as errors can delay the process or require corrective filings later.
Where and how the Y-tunnus is used
Once assigned, the business ID becomes a constant presence across all formal business activity in Finland. It appears on invoices, contracts, official correspondence, and tax filings. Finnish law requires that the Y-tunnus be displayed on business documents, and omitting it can create complications with both clients and authorities.
The Y-tunnus is used in the following key contexts:
- Tax reporting: All filings with the Finnish Tax Administration, including VAT returns and employer contributions, are linked to the Y-tunnus.
- Banking: Opening a Finnish business bank account requires the Y-tunnus, and financial institutions use it to verify the company’s legal status.
- Public procurement: Companies tendering for public contracts must provide their Y-tunnus as part of the qualification process.
- Invoicing: Both domestic and international invoices issued by Finnish companies must include the Y-tunnus for legal compliance.
- Business relationships: Partners and clients routinely use the YTJ portal to verify a company’s registration status before entering agreements.
For foreign companies doing business with Finnish partners, understanding the Y-tunnus system also helps in verifying the legitimacy of local counterparts before signing contracts or making payments.
Common mistakes when registering for a Y-tunnus
Even with a straightforward registration system, certain errors come up repeatedly and can slow down the process or create compliance issues down the line. Being aware of them in advance makes a significant difference.
Choosing the wrong business structure is one of the most consequential early decisions. The legal and tax implications of operating as a sole trader versus a limited liability company are substantial, and changing the structure later involves additional filings and costs. Taking time to understand the differences before submitting the startup notification avoids this problem entirely.
Incomplete or inaccurate information in the registration form is another frequent issue. Missing details about responsible persons, incorrect addresses, or vague business descriptions can lead to the PRH requesting corrections, which delays the issuance of the Y-tunnus.
Failing to register for the correct tax registers at the time of startup notification is a common oversight. If a company expects to have employees or reach the VAT threshold quickly, registering for the employer register and VAT register from the outset avoids the need for separate applications later.
Not notifying the Trade Register of changes after registration is an ongoing compliance issue. Finnish law requires that significant changes, such as a new business address, changes to the board, or amendments to the articles of association, be reported to the PRH within the legally specified timeframes.
Getting the registration right from the start sets a solid foundation for everything that follows. At Firmally, we work with entrepreneurs and growing businesses to navigate Finnish company registration accurately and efficiently, from selecting the right structure to ensuring all registers are correctly set up. If the process feels complex or time-sensitive, we are here to help. Contact us to discuss how we can support your business setup in Finland.
