South Korea Blocks Polymarket: What the Illegal Gambling Ruling Means for Accounting Firms and CFOs

South Korea's Korea Media and Communications Commission has ordered access to Polymarket to be blocked, ruling that the crypto prediction market constitutes an illegal gambling environment under existing South Korean law. The decision is a direct signal to accounting firms and CFOs advising clients with exposure to prediction markets or similar decentralised finance protocols: regulatory treatment of these platforms is hardening, and the technical architecture of a product no longer determines its legal character.

What the Korean Regulator Actually Decided

The Korea Media and Communications Commission concluded that Polymarket falls within two distinct legal categories under South Korean law. First, under the Criminal Act, it qualifies as information that facilitates gambling or the opening of a gambling venue. Second, under the National Sports Promotion Act, it constitutes prohibited analogous betting activity. Both findings were reached simultaneously, making the block broad in scope.

The Specific Conduct That Triggered the Finding

The commission did not rely on a single feature. Instead, it identified a cluster of operational characteristics that, taken together, crossed the line into illegal gambling territory. Those included:

• A winner-takes-all payout structure across markets covering politics, sports and weather outcomes
• Operating the markets themselves and setting the trading rules within them
• Providing crypto deposit, withdrawal and settlement infrastructure
• Collecting transaction fees from users

The combined picture, the regulator concluded, is a platform that organises speculative wagering on real-world outcomes for financial gain, regardless of the mechanism through which it does so.

Why Polymarket's Defence Was Rejected

Polymarket made three arguments to the commission. It had removed Korean-language services from its platform. It does not accept payments in Korean won. And it operates through noncustodial smart contracts rather than holding or directly managing user funds.

The commission rejected all three. On language and currency, the regulator's view appears to be that Korean users could and did access the platform irrespective of those measures. On the noncustodial architecture argument, the commission was explicit: technical characteristics such as decentralisation, trading interfaces and order books do not exempt a service from South Korean law. This is the most consequential part of the ruling for firms advising on DeFi or Web3 products, because it directly addresses the argument that smart-contract-based services sit outside regulatory reach.

South Korea in a Broader International Pattern

South Korea is not acting in isolation. France, Australia and Germany are among other jurisdictions that have previously taken action against or restricted access to Polymarket. The convergence of multiple regulatory systems on the same conclusion, that prediction markets with financial stakes constitute gambling regardless of their on-chain design, is relevant context for any firm building a cross-border compliance position.

South Korea's Regulatory Track Record on Crypto Enforcement

This ruling fits a broader pattern of assertive enforcement in Korea. The Financial Services Commission recently overhauled its VASP registration manual, tightening the obligations on virtual asset service providers operating in the country. Earlier in 2026, the sentencing of the Delio CEO to 15 years following a major crypto fraud case sent a clear message about the consequences of operating outside regulatory boundaries. Prediction markets and DeFi protocols are now clearly within the scope of that scrutiny, not outside it.

Firms with Korean clients or Korean-resident users should treat the Polymarket decision as a reference point, not an isolated event. Korea's regulators are demonstrating both the willingness and the legal framework to reach platforms that serve Korean users, even when those platforms are domiciled abroad, operate in a non-Korean language and do not directly custody funds.

Accounting and AML Implications for B2B Firms

For accounting firms, auditors and CFOs, the Polymarket block raises practical questions that go beyond whether a client holds prediction market positions.

How to Classify Prediction Market Positions on the Books

Prediction market contracts are not straightforward to classify under either IFRS or local Korean GAAP. A position on a binary outcome market has characteristics of a derivative, a contingent asset and, depending on jurisdiction, potentially an illegal contract. Where a client holds open positions on a platform that has been declared illegal in their jurisdiction, the accounting treatment needs to consider:

• Whether the asset is recoverable, given the access block and the legal status of the underlying activity
• Whether a provision or write-down is required if recoverability is in doubt
• The disclosure obligations in financial statements if material positions exist

The noncustodial nature of Polymarket's structure means that user funds typically remain in wallets controlled by the user, accessed via smart contract. An access block does not automatically destroy the on-chain position, but it does restrict the practical ability to trade or withdraw through the platform's interface. That distinction matters for asset recognition and for going-concern assessments if the positions are material.

AML and KYC Exposure

From an AML perspective, the commission's ruling has a direct read-across to transaction monitoring obligations. Any firm providing accounting, audit or compliance services to clients who have transacted on Polymarket using Korean addresses or Korean-linked wallets should consider whether those transactions need to be reviewed in light of the illegal gambling determination.

Under South Korea's Act on Reporting and Using Specified Financial Transaction Information, proceeds of illegal gambling can constitute predicate offences for money laundering. If a client received payouts from Polymarket markets after the point at which the activity became clearly illegal under Korean law, those receipts may carry AML risk that needs to be assessed and, where appropriate, reported. Firms should also review their own onboarding procedures: if a client's business model involves operating or facilitating access to prediction markets in Korea, that is now a materially higher-risk profile than it was before this ruling.

This is relevant context alongside our earlier coverage of the Binance user data case and its AML implications, which illustrated how cross-border data and transaction flows can create compliance exposure even when a firm believes its activities are technically outside a given jurisdiction. The same logic applies here: Korean regulatory reach extends to platforms serving Korean users, regardless of where those platforms are incorporated.

The Role of Crypto Accounting Software in Managing This Risk

Firms using crypto accounting software to maintain client ledgers should check whether their tooling captures on-chain positions held on noncustodial prediction market protocols. Standard exchange-based integrations will not pick up smart-contract positions unless the software explicitly supports DeFi wallet scanning. If a client has material Polymarket positions, those need to be surfaced in the accounting records, not left off-ledger because they sit outside a centralised exchange feed.

Choosing the right digital asset accounting software for clients with DeFi exposure is therefore not an abstract question. It has direct consequences for the completeness and accuracy of the financial statements, and for the firm's ability to identify AML risk in the transaction history. This point applies whether the client is a Korean entity or a multinational with Korean-resident beneficial owners.

Practical Steps for Firms and CFOs

Immediate Actions to Consider

The Polymarket block became effective on the date the commission issued its order. Firms advising Korean clients or clients with Korean exposure should move through a structured review rather than waiting for the situation to develop further.

The first step is to identify whether any client holds or has recently held positions on Polymarket or comparable prediction market protocols. This requires looking beyond exchange transaction histories to on-chain wallet data, particularly for clients who use noncustodial wallets.

The second step is to assess the accounting treatment of any identified positions, taking into account the recoverability question and any disclosure requirements under the applicable reporting framework.

The third step is to review AML transaction histories for any payouts received from Polymarket by Korean-domiciled clients, and to determine whether those receipts require a Suspicious Transaction Report under Korean law or equivalent reporting in the client's home jurisdiction.

The fourth step is to update client onboarding and risk-rating procedures to reflect the fact that prediction market exposure is now a higher-risk indicator in the Korean context. This applies to new clients and to annual reviews of existing ones.

Firms engaged in VASP compliance work in Korea should also cross-reference the updated VASP registration guidance, covered in detail in our analysis of the FSC Korea VASP registration manual overhaul, to understand how the prediction market ruling interacts with the broader licensing framework.

Longer-Term Compliance Positioning

The rejection of the noncustodial and smart-contract arguments by the Korean regulator is significant beyond this single case. It signals that any DeFi or Web3 product serving Korean users needs to be assessed against Korean law based on what it does economically and functionally, not on how it is technically structured. Firms advising clients who are building, investing in or operating DeFi protocols should factor this into their legal and compliance risk assessments now, rather than waiting for a formal enforcement action.

The international pattern, with France, Australia, Germany and now Korea all reaching similar conclusions about Polymarket, suggests that the gambling-law approach to prediction markets is becoming a default regulatory position rather than an outlier. A cross-border compliance strategy that relies on technical decentralisation to avoid local gambling laws is increasingly unlikely to hold.

Frequently Asked Questions

Does the Korean block on Polymarket affect users who hold positions through noncustodial wallets?

The access block restricts use of the platform's interface, but on-chain positions held in noncustodial wallets are not automatically destroyed. However, the practical ability to trade or exit those positions through the platform is restricted, which has implications for asset recoverability and accounting treatment.

Can a client's Polymarket payouts be treated as ordinary income for Korean tax purposes?

The commission's ruling that Polymarket constitutes illegal gambling complicates any straightforward income treatment. Korean tax and legal advice specific to the client's circumstances is required, particularly where payouts were received after the point at which the activity became clearly illegal under Korean law.

Does the noncustodial design of a DeFi protocol protect it from Korean regulation?

No. The commission explicitly rejected the argument that noncustodial architecture, decentralisation or smart-contract operation exempts a service from South Korean law. The functional and economic character of the service is what matters to Korean regulators, not its technical structure.

What AML obligations arise for accounting firms whose clients transacted on Polymarket?

Firms should review whether any payouts received by Korean-domiciled clients may constitute proceeds of illegal gambling, which can be a predicate offence for money laundering under Korean law. Where there is reasonable grounds to suspect this, a Suspicious Transaction Report may be required. Firms should also update client risk ratings accordingly.

How does this ruling affect VASP licensing decisions for firms considering the Korean market?

Any firm whose product includes prediction market features, outcome-based wagering, or similar structures should take legal advice on whether those features would be characterised as gambling under Korean law before seeking VASP registration. The FSC's updated VASP registration manual and this commission ruling together define a tighter operating envelope for crypto businesses in Korea.

Source: Cointelegraph