Scam messages have been sent out in the Tax Administration’s name. Read more about scams.

9A Capital gains and capital losses from trading with securities (3064) Forms

Report capital gains and capital losses from securities if the information is missing from your pre-completed tax return or if it is inaccurate. Also report disposals of foreign securities. Primarily submit the information in MyTax. If you cannot use MyTax, use a paper form or authorise another person to act on your behalf.

Choose your filing method

Please note that MyTax does not contain numbered forms, such as Form 9A.

  • If you sold securities last year, check and complete your pre-completed tax return.
  • If you have sold securities this year, report the capital gain or capital loss in your tax card application. 

Go to MyTax

How to file the selling of securities or other assets in MyTax

Return address is printed on the form.

Please note: If you report trading in securities during the trading year, do not use Form 9A but request a new tax card or prepayments.

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The online authorisation mandate

You can use the feature called “Suomi.fi Authorization” to enable you to deal with another person’s taxes through e-services, over the telephone, or by visiting a service point on their behalf.

See how to grant and request a Suomi.fi authorisation

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Letters of authorisation on paper

You can receive a letter of authorisation from the other person. It will enable you to deal with that person’s taxes on the telephone, by visiting a service point on their behalf, or by submitting information on paper tax forms. To have a letter of authorisation (often called a ‘power of attorney’) does not provide access to MyTax.

Letter of authorisation for tax representation of individual taxpayers (3818)

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When is there no need for an authorisation mandate?

The following circumstances are examples of when you can deal with someone else’s taxes with no authorisation.

You have child younger than 18 and you handle the child’s taxes

You are automatically authorised to access MyTax for the child, without an authorisation. Log in to MyTax and select “Act on behalf of someone else”.

Read more about this subject on Suomi.fi

You are a guardian

You do not need a Suomi.fi authorisation when your continuing power of attorney for being a guardian is officially confirmed, or when you are registered as a private guardian. Log in to MyTax and select “Act on behalf of someone else”.

Read more: “You are a private guardian or have a continuing power of attorney to act as guardian” on the Authorisations page

Note: If you are a public guardian, in other words, a public official employed by a public guardianship office, you can only use paper forms.

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Page last updated 12/19/2024