Tax Return for Investors: Complete Guide (2026)

As an investor in the Netherlands, you must declare your investments in Box 3 of your income tax return. Since 2025, the actual-returns system applies, which has changed everything.

Here is your complete guide to filing your tax return as an investor in 2026.

Box 3: Actual Returns (2025+)

The New System

Since 2025, you pay tax on your actual returns, no longer on a notional yield.

Formula:

Actual Return = (Value 31 Dec) - (Value 1 Jan) + (Withdrawals) - (Deposits)

Tax:

Taxable Return = Actual Return × (Assets above Allowance / Total Assets)
Tax Due = Taxable Return × 36%

Tax-Free Allowance (2026)

Situation	Tax-free Allowance
Single	€59,357
Fiscal Partners	€118,714

Example:

Assets on 1 January: €100,000
Assets on 31 December: €110,000
No deposits or withdrawals
Actual return: €10,000

Calculation:

Assets above allowance: €100,000 - €59,357 = €40,643
Taxable portion of return: €10,000 × (€40,643 / €100,000) = €4,064
Tax: €4,064 × 36% = €1,463

What Must You Declare?

Declare in Box 3

✅ Savings (bank accounts, savings accounts)
✅ Investments (stocks, ETFs, funds)
✅ Cryptocurrency
✅ Second home (not your primary residence)
✅ Gold, silver, precious metals
✅ Art and antiques (held as investment)
✅ Foreign investments

Do Not Declare

❌ Primary residence (Box 1)
❌ Household goods and personal effects
❌ Savings schemes (under certain conditions)
❌ Annuity policies (taxed in Box 1 on payout)
❌ Green investments (exempt up to €26,715, 2026)

Valuing Investments

How to Value

Reference date: 1 January of the tax year

Rule: Use the market value (waarde in het economische verkeer).

Examples:

Investment	Valuation
Stocks	Closing price 1 January
ETFs	Closing price 1 January
Funds	Repurchase value 1 January
Crypto	Closing price 1 January (e.g. via CoinMarketCap)
Savings	Balance on 1 January

Where to Find Prices?

Stocks/ETFs: Yahoo Finance, Google Finance, your broker
Funds: Fund manager’s website
Crypto: CoinMarketCap, CoinGecko, your exchange
Savings: Bank statement

Tip: Keep evidence of your valuations (screenshots, statements). The tax office can ask for substantiation.

Foreign Investments

Reporting Obligation

You must declare all worldwide assets, even if they are held at a foreign broker.

Examples:

Interactive Brokers (Ireland)
Degiro (Germany/Netherlands)
Trading 212 (Bulgaria)
eToro (Cyprus)

No Double Taxation

The Netherlands has treaties with many countries to prevent double taxation.

Dividend tax:

US: 15% withheld (offset via Irish-domiciled ETFs)
Netherlands: no additional levy in Box 3

Important: Under Box 3 you only pay Dutch tax on the return. Foreign withholding tax on dividends is generally not creditable in Box 3.

Crypto Specifics

What Must You Declare?

✅ All crypto on exchanges (Bitvavo, Coinbase, etc.)
✅ Crypto in your own wallets (Ledger, MetaMask, etc.)
✅ Stablecoins (USDT, USDC, DAI)
✅ NFTs (held as investment)
✅ Staking rewards (they increase your holdings)

Valuation

Use the EUR value on 1 January. For example:

1 BTC on 1 January 2026: €85,000
You hold 0.5 BTC → Value: €42,500

Staking and DeFi

Staking rewards:

Not taxed separately as income
Increase your crypto holdings
Value on 31 December is higher → higher return

DeFi positions:

Liquidity pool tokens: value at market price
Impermanent loss: may result in lower return (or loss)

Offsetting Losses

Losses in Box 3

Losses can be offset against gains within the same year.

Example:

Stocks: +€8,000
Crypto: -€3,000
Net return: €5,000

Carry Losses Forward?

No. Losses cannot be carried forward to other years.

Strategy: Realise losses in years with high gains to reduce your tax bill.

Tips to Optimise Your Tax

1. Use Each Partner’s Allowance

Fiscal partners have €118,714 free between them.

Example:

Partner A: €80,000 in assets
Partner B: €80,000 in assets
Combined: €160,000

Optimised:

Split assets evenly: €80,000 each
Tax-free: €59,357 × 2 = €118,714
Taxable: €160,000 - €118,714 = €41,286

Not optimised:

Partner A: €160,000, Partner B: €0
Tax-free: €59,357 (only A)
Taxable: €160,000 - €59,357 = €100,643 (much higher!)

2. Green Investments

Green investments are exempt up to €26,715 per person (2026; this amount is being phased out for higher wealth brackets).

⚠️ Important: The tax benefit for green investments will be abolished from 2028 as part of Belastingplan 2026. Keep this in mind when planning your investments.

Condition:

Investment must be on the tax office’s approved list
Maximum exemption: €26,715 × 2 = €53,430 for partners

Examples:

Triodos Sustainable Fund
ASN Sustainable Fund
Certain green bonds

3. Timing of Gain Realisation

Under the actual-returns system:

Unrealised gains are counted (value 31 Dec vs 1 Jan)
Losses can offset gains

Strategy:

Realise losses in years with high gains
Hold losing positions until a year with lower gains

4. Keep Assets Below the Allowance

If your assets stay under €59,357 (per person):

No Box 3 tax
Still a filing obligation (if you have other Box 3 assets)

Ways to do this:

Pay off more on your mortgage (primary residence is not in Box 3)
Contribute to an annuity policy (reduces Box 3, but taxed later in Box 1)
Spread assets across partners

Filing: Step by Step

Preparation (January)

Record all balances on 1 January
- Bank accounts
- Brokerage accounts
- Crypto wallets
- Other assets
Gather evidence
- Bank statements
- Broker overviews
- Crypto exchange statements

During the Year

Track transactions
- Deposits
- Withdrawals
- Large purchases/sales

Filing the Return (March-May)

Log in to Mijn Belastingdienst
- Use DigiD
- Go to “Aangifte inkomstenbelasting”
Fill in Box 3
- Assets on 1 January
- Assets on 31 December
- Deposits and withdrawals
Check the pre-filled data
- The tax office already has a lot of data
- Verify that everything is correct
- Add missing data (e.g. crypto)
Submit before the deadline
- Standard: 1 May
- Extension possible until 1 September

Common Mistakes

1. Forgetting Crypto

Crypto in your own wallets is often forgotten. You must declare all crypto, including in non-custodial wallets.

2. Forgetting Foreign Accounts

Investments at Interactive Brokers, Trading 212, etc. must also be declared.

3. Wrong Valuation

Use the value on 1 January, not the average value or the value on another date.

4. Forgetting Deposits/Withdrawals

These are needed for the actual-returns calculation.

5. Forgetting Your Partner

Fiscal partners can save a lot of tax by distributing assets correctly.

Tax Office Audits

How Does the Tax Office Check?

Automatic data exchange
- Dutch banks provide data
- Brokers are increasingly doing so too
DAC8 (from 2026)
- Crypto exchanges must share data
- Tax office automatically receives crypto data
Bank transactions
- Large transfers to exchanges stand out
Random checks
- Spot audits

What Happens in an Audit?

The tax office can ask for:

Bank statements (1 January and 31 December)
Broker overviews
Crypto wallet addresses and transaction history
Substantiation of valuations

Tip: Keep your records for at least 7 years.

When to Engage a Tax Advisor?

Consider professional help if:

✅ Assets over €200,000
✅ Complex foreign structures
✅ Crypto trading as main income (possibly Box 1)
✅ Questions from the tax office
✅ Uncertainty about Box 1 vs Box 3

Cost: €150-400 for a standard return with investments.

Important Dates (2026)

Date	What
1 January 2026	Box 3 reference date
1 March 2027	Return can be filed
1 May 2027	Filing deadline
1 April 2027	Extension request deadline
1 September 2027	Deadline with extension

Bottom Line

As an investor in the Netherlands, you must declare your investments in Box 3. Since 2025, you pay tax on your actual returns (36% above the €59,357 allowance).

Key points:

Record your assets on 1 January and 31 December
Declare all worldwide assets (including crypto)
Use each partner’s tax-free allowance as fiscal partners
Keep good records

The tax office is getting better at tracing investments, especially crypto. Filing honestly is the safest strategy.

Last verified: 2026-05