According to disclosures by multiple crypto media outlets and X platform users, the Web3 banking protocol Fiat24 recently sent emails to some registered users, requesting them to . Users need to prepare the following information: first, the country or countries in which they are tax residents; second, the corresponding Tax Identification Number (TIN) for each country. For mainland Chinese users, their personal ID card number serves as the Tax Identification Number. According to kajiQ, the Chinese-language spokesperson for Bitget Wallet, the affected individuals are primarily a small number of users who completed KYC and opened cards using their passports prior to January 1, 2026. Fiat24 requires relevant users to follow the guidelines and complete the information supplementation by July 31, 2026; otherwise, their accounts will face the risk of cancellation in accordance with regulations.
Although Fiat24's recent small-scale request for users to supplement tax resident identity information is based on the compliance and regulatory requirements of the Common Reporting Standard (CRS), it has still aroused concerns among some mainland investors: Fiat24 itself is an upstream issuer of crypto cards (U-cards) such as those of Bitget, and an ID card number is . Will mainland tax authorities utilize CRS information exchange to acquire their offshore crypto asset information, thereby demanding supplementary tax payments?
Starting from Fiat24's reporting obligations and the operational mechanism of CRS, mainland users will not inevitably be subject to tax recovery after supplementing their TIN; however, the possibility of subsequently being asked to explain the source of , cost basis, and historical reporting status is objectively elevated. Taking the event of Fiat24 requesting supplemental Tax Identification Numbers as a starting point, this article will provide of the continuous deepening trend of transparent regulation of crypto assets behind this supplementation event.
Fiat24 is operated by SR Saphirstein AG, a Swiss company holding a Fintech license issued by the Swiss Financial Market Supervisory Authority (FINMA) in accordance with Article 1b of the Federal Banking Act. In terms of its core business, Fiat24 accepts user deposits and provides payment account services to users in a licensed manner, which complies with the definition of a Depository Institution under the CRS. According to the Swiss Federal Act on the International Automatic Exchange of Information in Tax Matters (AEOIA) and relevant administrative ordinances, financial institutions holding a FINMA license and conducting deposit businesses are, in principle, required to fulfill CRS reporting obligations.
As for which accounts need to be reported under the CRS framework, the following conditions must also be met: First, the account must be a financial account as defined by the CRS; Second, the account holder must be a tax resident of another CRS participating jurisdiction. Fiat24's deposit accounts clearly constitute financial accounts under the CRS, and both China and Switzerland are CRS participating jurisdictions, having established an automatic exchange of financial account information relationship in 2018. Therefore, if Chinese tax residents hold accounts on Fiat24, there is naturally a possibility that their account information will be transmitted back to mainland tax authorities.
Since Fiat24 inherently bears CRS reporting obligations, why are some early users only now being asked to supplement tax information such as their TIN? The official announcement , but core reason for this supplementation may lie in a mismatch between the user's account opening identification document and their TIN. indicate that for individuals using a Chinese resident ID card as proof of identity, the TIN is the ID card number; however, for individuals using a passport or other documents as proof of identity, the TIN is typically issued by local tax authorities in accordance with relevant rules. If mainland Chinese users use a resident ID card to open an account, the document number itself can serve as the TIN; but if they open an account using a passport, the passport number does not automatically equate to a TIN. If the platform only retains the passport number, it may be unable to complete the tax identification fields required for CRS reporting. Meeting the requirements of CRS compliance regulation is a compelling explanation for Fiat24 notifying some users to supplement their tax information at this time.
The reason the aforementioned gap was not immediately discovered when opening an account with Fiat24 may also be related to the different due diligence standards set by the new and old CRS for new accounts versus preexisting accounts. For new accounts, the CRS requires financial institutions to obtain a self-certification containing the TIN upon account opening; whereas for preexisting accounts, if the TIN is not present in the relevant records and local laws do not mandate its retention, the institution is not required to collect it immediately upon account opening, but must supplement it within two years through Reasonable Efforts. Here, "Reasonable Efforts" means "genuine attempts to acquire the TIN from the preexisting account holder," which must be ongoing at least from the time the account is identified as a reportable account until the end of the second calendar year. However, during the period of reasonable efforts, it is not necessarily required to close, freeze, or restrict the account, nor is it required to link the use of the account to the provision of the TIN. Therefore, under the compliance requirements at that time, the involved in this event could complete KYC identity verification and use their accounts normally with only a passport. However, under the current requirements of CRS 2.0, financial institutions need to complete comprehensive tax information collection right at the account opening stage, including confirming the account holder's tax resident status and TIN. For Chinese users who opened accounts early on using a passport but did not retain a TIN, their accounts constitute information gap accounts under the preexisting account category, and Fiat24 must continuously take reasonable measures to supplement this information.
According to the CRS framework, financial institutions identify accounts opened by tax residents of other countries or regions through due diligence, and annually report to local competent authorities information such as the account holder's name, TIN, address, account number, account balance, as well as interest, dividends, and gross proceeds from the sale of financial assets. The relevant information is then exchanged between the competent tax authorities of the country or region where the financial institution is located and the competent tax authorities of the account holder's country of residence.
, what user-related information might be reported?
The first category is CRS financial account information, including name, address, TIN, account number or functional equivalent, year-end account balance or value, and relevant income items. These are the contents directly covered by the CRS mechanism.
The second category is crypto transaction information, which typically includes users' trading records of buying and selling BTC, ETH, stablecoins, or other tokens on exchanges, cost bases, and on-chain transfer paths. However, CRS information reporting does not cover complete crypto transaction information: if the account merely holds a Fiat24 account balance pegged to fiat currency, the reporting focus is more likely to be the account balance and related income rather than the user's entire on-chain transaction history. According to the latest OECD CRS guidelines, the balances of various currencies under multi-currency electronic money products should be aggregated and reported as a single deposit account, and the CRS currency translation rules shall apply.
Starting from the operational mechanism and coverage scope of the CRS, the information reporting involved after Fiat24 supplements the TINs for some mainland users remains limited to the current provisions of the CRS and does not directly involve the users' crypto asset transaction information. However, once information regarding account balances, inflows and outflows of funds, and related income is bound to an individual's tax identity, it may subsequently become the basis for tax authorities to judge the source of funds and potential taxable income, objectively elevating the likelihood of these users being subject to tax recovery in the future.
From an overall market perspective, multiple events, including Fiat24's supplementation of tax information, collectively reflect the expansion of the global trend towards financial information transparency into the crypto asset sector. Since January 2026, Bitvavo has required new users to submit their place of birth, tax resident status, TIN, and self-certification information upon account opening, and existing users are also required to supplement these subsequently. OKX Europe, Coinbase, bitFlyer Europe, Kraken, and VALR have also all clarified in their user-facing FAQs that the platforms may require users to supplement or confirm their tax resident status and TIN based on DAC8 or the CARF; for users who fail to complete this as required, certain services may be restricted. On an institutional level, the transparent regulation of crypto assets revolves primarily around the amendments to the CRS and the CARF.
In August 2022, the OECD completed the amendments to the CRS framework, bringing specific electronic money products and Central Bank Digital Currencies (CBDCs) into the reporting scope; the OECD also clarified that indirect investments in crypto assets through derivatives and investment vehicles are also subject to the jurisdiction of the CRS framework. Certain products with the attributes of payment accounts, stored-value accounts, or on-chain fiat accounts, even if they do not belong to typical crypto exchange accounts, may also enter the existing financial account information exchange chain.
In October 2022, the OECD launched the Crypto-Asset Reporting Framework (CARF), requiring Crypto-Asset Service Providers to report user transaction information regarding crypto assets to tax authorities in a standardized manner, bridging the gap of insufficient coverage of crypto asset transaction information under the traditional CRS. Although mainland China has not yet officially announced its participation in the CARF, the Hong Kong region already plans to submit legislative proposals in 2026. This would mandate reporting Crypto-Asset Service Providers to collect the information required by the CARF starting in 2027, with the Inland Revenue Department conducting its first exchanges with partner jurisdictions starting in 2028, which may provide tax authorities with more clues to identify the tax-related risks of mainland users.
As the CRS amendments and the CARF are gradually implemented, the compliance space for asset arrangements that rely on offshore platform operations and are premised on information opacity is continuously narrowing. The transparent regulation of crypto assets has become an irresistible realistic trend, and the comprehensive cost of passively waiting for investigation is often far higher than proactive declaration. In the long run, it is necessary for overseas asset investors to inventory offshore financial accounts under their names, adjust existing tax planning, and consult professional tax advisors for an evaluation tailored to their specific circumstances.
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