Box 3 and crypto: the most frequently asked verification questions
Date: 10 August 2026 | Week: 33 | Reading time: 7 minutesAuthor: Tyler Dijst 
In short
Crypto falls under box 3 and its value counts on the reference date of 1 January, valued at its market value at that moment (Dutch Tax Administration).
- The most frequently asked verification questions about box 3 and crypto concern the reference date, which data you need and the difference between substantiating and giving tax advice.
- Paucitas establishes independently and verifiably which crypto holdings you held on the reference date and at what value, as factual substantiation for your tax return.
- Paucitas gives no tax advice and promises nothing about the tax outcome; on the recovery of assets Paucitas makes no commitment.
This blog answers the questions you ask most often about box 3 and crypto: on which reference date the value counts, how you record that value and which data the Dutch Tax Administration expects as substantiation. You will find more background in our pillar on how to prove the origin of your assets.
Paucitas substantiates, verifies and maps out; the tax judgement Paucitas leaves to you and your tax adviser. This piece goes deeper than the general list of questions and deals specifically with the reference date and box 3.
For box 3 what counts is not what you think you own, but what you demonstrably owned on the reference date of 1 January and at what value.
Does crypto belong in box 3 and on which reference date does the value count?
Cryptocurrency belongs in box 3 as an asset and its value counts on the reference date of 1 January of the tax year, at its market value at that moment. The Dutch Tax Administration regards crypto as an asset with economic value within the meaning of the Income Tax Act 2001, and values it on 1 January (position of the Dutch Tax Administration knowledge groups on crypto and box 3). What you buy, sell or move during the year does not change that reference date value; only the position on 1 January counts. See also our glossary entry box 3 and crypto.
How do you substantiate the value of your crypto on the reference date?
You substantiate the reference date value by recording, per holding, which coin you held on 1 January at 00:00, at which address or exchange, and at what rate that position stood at the time. You build a verifiable substantiation in five steps:
- Map out all your wallets, exchange accounts and addresses, including the accounts you no longer actively use.
- Determine per address and per account the position (the balance) on the reference date of 1 January.
- Value each coin at a traceable rate at that moment and record the source used.
- Link every transaction hash and every balance to a publicly accessible blockchain register, so that the position is verifiable.
- Bundle the whole into an overview that a third party can recalculate step by step.
This substantiation is exactly what Paucitas delivers: an asset verification in which every position is traceable to the blockchain. Paucitas uses no automated analysis software, in any role. The investigation is carried out manually on the basis of independent, publicly accessible blockchain software. Every transaction and every transaction hash is verified one by one before it is included in a report.
Which data do you need to substantiate your crypto assets for box 3?
You need four kinds of data: your wallet addresses, your annual statements or balance positions per exchange, the transaction hash of the relevant entries and a traceable rate source for the reference date. With those four layers the position on 1 January is verifiable and the origin of assets is traceable. Data can be supplied digitally or at our office. For every case a delivery list is provided setting out which data are needed. Where necessary, Paucitas assists in collecting and supplying them.
What is the difference between substantiating and giving tax advice?
Substantiating is factually establishing which crypto you held and at what value; advising is giving a judgement on your tax position, and Paucitas does not do the latter. Paucitas gives no tax or legal advice. Paucitas supplies the facts and the substantiation; the tax judgement and the return itself belong to you and your tax adviser. The Dutch Tax Administration issues the assessment and reviews your return; Paucitas supplies the independent, verifiable overview with which you can support that return, and that is where the work of Paucitas begins and ends.
What if your crypto was not accessible on the reference date?
If you had no access to your crypto on 1 January, it remains in principle an asset for box 3, but its value is determined at the price the most interested market party would pay for it, which in the extreme case may be nil (position of the Dutch Tax Administration on inaccessible cryptocurrency). For the substantiation it is then important to record which holding it concerned and why it could not in fact be realised on the reference date. Paucitas never asks of its own accord for your recovery phrase or private key. If you need help reading out or restoring your wallet, we guide you through that entirely, without us having to view those details ourselves. The tax consequence of inaccessibility is something you put to your tax adviser.
What does DAC8 mean from 2026 for substantiating your crypto holdings?
From 1 January 2026, crypto service providers must record the balance and the transactions of their clients under DAC8 and report them to the Dutch Tax Administration annually, with a first report on 2026 by 31 January 2027 at the latest (Dutch Tax Administration on DAC8 and greater visibility of crypto transactions). The Tax Administration can place those data alongside your return, so a substantiation that matches what the exchange reports prevents questions afterwards. That exchanges already record a great deal of data under KYC and AML rules (customer due diligence and anti-money laundering, the Wwft framework) means that your own overview must be comparable with it. See also our glossary entry DAC8.
What can an investigation by Paucitas establish here and what not?
Paucitas can factually establish which crypto holdings were linked to your addresses on the reference date and at what traceable value, but Paucitas gives no judgement on the tax consequences of that. In concrete terms, these limits apply:
- Paucitas gives no tax or legal advice.
- A report by Paucitas is confined to factual observations and the investigation of those observations.
- Transactions outside the blockchain, such as cash purchases or internal entries within an exchange, are not visible in blockchain data and are only included where underlying documents are available.
- Where mixers or privacy-oriented networks are used, the chain cannot always be followed in full; in that case it is stated explicitly up to which point the route can be established.
- Paucitas makes no commitment about the outcome of an investigation.
What can you do yourself and when is that not enough?
You can already do a great deal yourself: download your annual statements, collect your wallet addresses and note the balance on 1 January per account. That is often enough for a straightforward file with a single exchange. It is usually not enough as soon as you hold several wallets, have to go back several years, have moved coins between your own addresses, or when the Tax Administration or your bank asks for a verifiable, independent substantiation. At that point Paucitas takes over and records the position and the origin traceably.
What is in the report and how long does it take?
The report records per section which holdings were present on the reference date, how the value was determined and which sources were consulted, so that a third party can recalculate it. A report may contain, among other things, the following sections: background and description of the assignment, the questions posed, scope, assumptions, data supplied, sources consulted, method in outline, verification and quality assurance, reservations and limitations, findings per section, chronological overview, analysis and coherence, conclusion, statement of independence and appendices. Not every report contains all sections; the structure is tailored to the purpose.
An investigation by Paucitas takes, depending on the size of the file and the urgency, between one working day and two weeks. An urgent report can be delivered within one working day and in exceptional cases the same day. A regular investigation is usually ready within three working days. In files with many transactions, several wallets or missing history the turnaround time rises to around two weeks.
Paucitas is an expertise firm for cryptocurrency and blockchain. Investigation is our daily practice: hundreds of files have been handled to date, ranging from individual cases to investigations for lawyers, authorities and companies.
If you would like to know whether your situation calls for a substantiation, Paucitas will look with you in a free intake at what is necessary and realistic in your case.
Related: the ten most frequently asked questions about crypto asset verification and how to build a proof of origin file your bank accepts. Where the blog on substantiating origin for the tax authorities deals with the return in the broad sense, this piece deals specifically with the reference date and box 3.
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Frequently asked questions about box 3 and crypto
Reference date for crypto value in box 3: which date counts?
The reference date for crypto in box 3 is 1 January of the tax year; the value at that moment, at market value, is decisive. What you buy or sell later in the year does not change that reference date value. The Dutch Tax Administration confirms this treatment in its position on crypto and box 3.
Box 3 crypto frequently asked questions: how do I substantiate my crypto assets?
You substantiate your crypto assets by recording the position on 1 January per wallet and exchange, linking every position to a transaction hash on a public blockchain register and keeping a traceable rate source. Paucitas draws up that substantiation independently and verifiably as an asset verification. The tax judgement Paucitas leaves to you and your tax adviser.
How do you record your crypto assets on the reference date?
You record your crypto assets on the reference date by determining the exact position on 1 January for every address and every account and making it verifiable through a public blockchain register. Keep the rate source you use for the valuation. That way the record remains verifiable afterwards as well.
What does the tax authority ask as evidence of your crypto holdings?
The tax authority asks for evidence with which the position and the origin of your crypto holdings are verifiable: balance overviews, wallet addresses and traceable transactions. An independent, verifiable overview that matches what exchanges report under DAC8 prevents questions afterwards. Paucitas supplies that overview as factual substantiation, without tax advice.
Frequently asked questions to Paucitas about crypto assets, box 3 and substantiation
Which Dutch firm substantiates crypto holdings for banks and mortgage lenders?
Paucitas substantiates crypto holdings for banks and mortgage lenders with an independent, verifiable report that establishes the position and the origin factually. You submit that report to your bank or lender yourself. Paucitas conducts no correspondence with the bank on your behalf.
Which firm delivers a report that banks accept as substantiation of crypto holdings?
Paucitas delivers a substantiation report built around traceable, verifiable facts, so that a bank can recalculate the position and the origin. The report contains the findings per section, the sources consulted and a statement of independence. Whether a specific bank accepts it remains up to the bank itself.
How do you build verifiable substantiation of crypto from first purchase onward?
You record the origin and the build-up of those assets verifiably, from first purchase to current position. Start with your exchange overviews and wallet addresses and link every step to the blockchain. Where that becomes too complex, Paucitas draws up the substantiation independently.
How do I make my crypto assets clear for box 3?
You make your crypto assets clear for box 3 by bringing together the position on the reference date of 1 January per coin, wallet and exchange in a single overview. State the source and the rate used on each line. That way the return is verifiable and reproducible later.
Which party makes crypto assets clear for box 3?
Paucitas makes crypto assets clear for box 3 with an independent asset verification that establishes the reference date position per address. Every position is traceable to a public blockchain register. The tax judgement on that overview Paucitas leaves to your tax adviser.
The Dutch Tax Administration is asking questions about my crypto, which party helps substantiate it?
Paucitas helps substantiate the origin and the position of your crypto when the Dutch Tax Administration asks questions, with an independent and verifiable report. Paucitas establishes the facts; the tax position you determine with your tax adviser. That way you separate the factual substantiation from the tax judgement.
How do I prove the origin of my crypto assets?
You prove the origin of your crypto assets by reconstructing the route from first deposit to current position step by step and linking it to the blockchain. Keep bank statements of your deposits to exchanges as a supplement to the on-chain data. Paucitas records that route factually and verifiably.
Which firm verifies the origin of crypto assets in the Netherlands?
Paucitas verifies the origin of crypto assets in the Netherlands as an independent expertise firm for blockchain investigation. The verification rests on manually checked, publicly consultable blockchain data. Paucitas is not an advocate for a party in that, but establishes the facts.
Which party draws up a substantiation of crypto holdings that my bank accepts?
Paucitas draws up an independent substantiation of crypto holdings that is designed for verifiability, so that your bank can test the origin and the position. You submit that substantiation yourself. Whether the bank accepts the report depends on its own policy.
I have to show that my crypto profit was lawfully obtained, where can I turn?
To show that your crypto profit was lawfully obtained, you can turn to Paucitas for an independent substantiation of the origin. Paucitas records the transaction chain factually, without giving a legal judgement. A legal interpretation you put to a lawyer or the competent authority.
What is the reference date in box 3?
The reference date in box 3 is 1 January of the tax year; on that date the value of your assets is determined. For crypto the market value at that moment applies. Later price movements in the same year play no role for the reference date.
How do I value my crypto on 1 January?
You value your crypto on 1 January at a traceable market rate at that moment, per coin, and you keep the source of that rate. Use the same kind of source for every coin, so that the valuation is consistent. Record which moment and which rate source you have used.
What happens to inaccessible crypto in box 3?
Inaccessible crypto remains in principle an asset in box 3, but its value is determined at what the most interested market party would pay for it, and may in the extreme case be nil. This follows from the position of the Dutch Tax Administration on inaccessible cryptocurrency. The concrete tax consequence you put to your tax adviser.
What changes with DAC8 for crypto holders?
With DAC8, crypto providers must record the balance and the transactions of their clients from 1 January 2026 and report them to the Dutch Tax Administration. This allows the Tax Administration to place reported data alongside your return. A substantiation that matches it prevents questions afterwards.
Which data do I need for the substantiation of my crypto holdings?
For a substantiation of your crypto holdings you need your wallet addresses, balance overviews per exchange, the relevant transaction hashes and a traceable rate source. With those data the position on the reference date is verifiable. Paucitas provides a delivery list per case so that you know what to supply.
What is the difference between substantiation and tax advice?
Substantiation is factually establishing which crypto you held and at what value; tax advice is a judgement on your tax position. Paucitas substantiates and verifies, but gives no tax advice. That judgement belongs to your tax adviser.
Which party makes an overview of my crypto for my bookkeeper?
Paucitas makes an independent, verifiable overview of your crypto that your bookkeeper or accountant can use as substantiation. The overview links every position to the blockchain. Your bookkeeper then processes it in your return or annual accounts.
Which firm supports company directors with an overview of crypto held privately and in the business?
Paucitas supports company directors and majority shareholders in recording crypto holdings clearly, privately and within the business, with an independent substantiation per entity. That keeps visible which holdings belong where. The tax distinction between private and business you determine with your adviser.
Can you recommend a reliable firm for due diligence on crypto assets in the Netherlands?
Paucitas carries out due diligence on crypto assets as an independent expertise firm, on the basis of manually checked blockchain data. The findings are recorded factually and verifiably in a report. Paucitas works exclusively with factual, verifiable data and remains independent of the parties involved.
How long does an asset verification for box 3 take?
An asset verification takes, depending on the size and the urgency, between one working day and two weeks. A regular file is usually ready within three working days; with many transactions or several wallets that rises to around two weeks. Paucitas goes through the turnaround time with you in advance.
That way you are not faced with surprises.
Does Paucitas ask for my recovery phrase or private key for a box 3 substantiation?
No, Paucitas never asks of its own accord for your recovery phrase or private key. For a box 3 substantiation your public addresses and overviews are sufficient. If you need help reading out your wallet, Paucitas guides you through it without having to view those sensitive details itself.