Tokeny Solutions and ERC-3643: The European Standard for Tokenized Securities

Overview

Tokeny Solutions, headquartered in Luxembourg, occupies a singular position in European tokenized securities infrastructure. The company developed and continues to steward ERC-3643 — the Ethereum token standard formally accepted by the Ethereum community that embeds identity verification and compliance enforcement directly into the token contract layer. Where most token standards define only the mechanics of transfer (ERC-20) or uniqueness (ERC-721), ERC-3643 adds a mandatory compliance layer: transfers are only permitted if both sender and receiver hold verified, on-chain identity credentials that satisfy the issuer’s investor eligibility rules.

That architecture has made ERC-3643 the preferred technical standard for regulated securities issuances in Europe, with institutional adopters including Société Générale, Euroclear, BNP Paribas, CACEIS, and others. The standard is sometimes referred to as T-REX — Token for Regulated EXchanges — reflecting its original internal designation before formal Ethereum Improvement Proposal submission.

Luxembourg Headquarters and CSSF-Aligned Compliance

Tokeny’s Luxembourg base is not incidental. Luxembourg is the domicile for approximately 65% of European UCITS funds and a dominant jurisdiction for alternative investment fund (AIF) structures under the AIFMD. The Commission de Surveillance du Secteur Financier (CSSF) — Luxembourg’s financial regulator — has been among the more technically engaged European regulators on digital securities questions, publishing guidance on blockchain use in fund administration and engaging with domestic fintech firms.

Operating from Luxembourg positions Tokeny to serve the fund administration and transfer agency functions that Luxembourg-domiciled vehicles require. UCITS funds have strict shareholder registry requirements; AIFs have investor eligibility and redemption gate obligations. ERC-3643’s on-chain compliance enforcement aligns with these obligations in ways that a generic ERC-20 transfer does not — the token contract itself refuses ineligible transfers, creating a technical enforcement layer that complements the issuer’s contractual and regulatory obligations.

The CSSF has not issued a specific approval of ERC-3643, and Tokeny does not hold CSSF authorization as a fund administrator or transfer agent in its own right. Rather, Tokeny provides technology that regulated entities use to discharge their own compliance obligations. The contractual architecture matters: the issuing entity (fund, bank, or corporate) remains the regulated party; Tokeny provides the technical infrastructure under a licensing or service arrangement.

ERC-3643 Technical Architecture

The ERC-3643 standard comprises several interacting components, each serving a distinct compliance function.

ONCHAINID is the decentralized identity standard that underpins ERC-3643. Each investor receives an ONCHAINID — a smart contract deployed on Ethereum that stores verified identity claims issued by trusted claim issuers (KYC providers, compliance officers, or regulated identity verifiers). Claims follow the ERC-735 format and include attributes such as country of residence, accreditation status, AML clearance, and custom eligibility flags set by the issuer.

Identity Registry is a contract maintained by the token issuer that maps wallet addresses to ONCHAINID contracts. Only wallets associated with registered, claim-verified identities can receive token transfers.

Compliance Module is a configurable smart contract that encodes the specific transfer rules applicable to a given security: maximum investor count, jurisdictional whitelists and blacklists, lockup periods, concentration limits, and custom eligibility conditions. The compliance module is called before every transfer and can be updated by the issuer within the bounds of applicable regulations.

Transfer Manager provides governance over token operations — pausing, freezing individual wallets, forced transfers in court-ordered scenarios — giving issuers the administrative controls that securities regulations in most jurisdictions require for registered instruments.

This four-component architecture means that compliance logic is modular and upgradeable without replacing the token itself. A change in jurisdictional eligibility rules — for example, following a new ESMA guideline — can be implemented by updating the compliance module rather than reissuing the token.

Societe Generale and the OFH Tokens

Société Générale’s structured products subsidiary, SG-FORGE, used ERC-3643 and Tokeny’s infrastructure to issue covered bonds — Obligations de Financement de l’Habitat (OFH tokens) — directly on the Ethereum mainnet. The OFH tokens represented legal covered bond obligations on-chain, denominated in euros, and subject to French covered bond law (the Loi Scrivener framework for obligations foncières).

This issuance was notable for several reasons. First, it used Ethereum mainnet — a public, permissionless blockchain — rather than a permissioned enterprise chain, relying on ERC-3643’s compliance enforcement to restrict token transfers to eligible institutional investors. Second, the tokens were issued directly by a regulated bank subsidiary and constituted legal debt obligations enforceable under French law. Third, the issuance demonstrated that ERC-3643’s compliance architecture could satisfy the investor eligibility requirements of a heavily regulated financial instrument without requiring a permissioned chain.

The French Autorité des Marchés Financiers (AMF) and the Autorité de contrôle prudentiel et de résolution (ACPR) have both engaged with SG-FORGE’s activities, including an experimental use of the EUR CoinVertible (EURCV) stablecoin for on-chain settlement of the bond.

Euroclear and Post-Trade Integration

Euroclear, the Brussels-based central securities depository that holds approximately €40 trillion in assets under custody, has worked with Tokeny on digital securities settlement infrastructure. The engagement reflects a broader question facing traditional post-trade infrastructure: as tokenized securities are issued on blockchain ledgers, what role does an ICSD play, and how does the ICSD’s settlement and custody function interact with on-chain transfer mechanics?

The Tokeny architecture offers one answer: ERC-3643 tokens can be issued with Euroclear as the identity registry authority — meaning Euroclear’s existing KYC and investor eligibility records are the source of claim issuance for ONCHAINID. In this model, on-chain compliance enforcement is anchored to Euroclear’s regulated identity infrastructure, and Euroclear’s ledger and the blockchain ledger can be maintained in synchronized form through bridge architecture.

UCITS and AIF Tokenization Use Cases

The primary European fund tokenization use cases for ERC-3643 involve UCITS and AIF fund share classes. A UCITS fund issuing a tokenized share class faces a set of regulatory requirements that map precisely onto ERC-3643’s features: the fund must maintain a shareholder register (Identity Registry), restrict subscription and redemption to eligible investors in eligible jurisdictions (Compliance Module), allow forced transfer in exceptional circumstances (Transfer Manager), and issue verified investor credentials (ONCHAINID claims issued by the fund’s transfer agent).

The ERC-3643 Association — an industry body formed to govern the standard’s development — has published reference implementations of compliance modules for UCITS and AIF eligibility rules, reducing the integration burden for asset managers seeking to tokenize fund shares without building bespoke compliance smart contracts.

For private equity and debt fund tokenization, the ERC-3643 architecture supports the specific requirements of professional investor restrictions under AIFMD, the maximum investor count thresholds relevant to certain exemptions, and the side pocket mechanisms sometimes required for illiquid asset class exposures.

Open Source and Ecosystem Development

ERC-3643’s governance structure is relevant to compliance officers evaluating platform lock-in risk. The standard is open-source (MIT license), maintained by the ERC-3643 Association, and the reference implementation is publicly audited. Any technology provider can implement ERC-3643-compatible tokens without a commercial relationship with Tokeny — and several have done so.

Tokeny’s commercial position is therefore dependent on its implementation quality, integration support, and institutional relationships rather than proprietary lock-in through the standard itself. This structure mirrors how SWIFT or FIX protocols work: the standard is open, but implementation and connectivity services generate commercial revenue.

For issuers, this means ERC-3643 tokens issued today through Tokeny’s platform are technically compatible with any ERC-3643-aware transfer agent, custody provider, or secondary market venue — a degree of interoperability that proprietary token standards cannot offer.

Further Resources

• Tokeny Solutions official platform
• ESMA — EU Securities Regulation
• MiCA Regulation Overview
• Jurisdiction Profiles — Luxembourg
• Tokenization Licensing Overview