Coinone

Is Coinone safe?

Coinone is one of the safer places for a Korean resident to keep won and coins, with one clear weakness. We found no theft from its own wallets in twelve years, its accounts are audited and public, and Korean law keeps customer cash at a bank and most coins offline. The catch is compliance: in April 2026 regulators found tens of thousands of anti-money-launderingAnti-money launderingThe rules and checks that stop criminals from moving illegal money through banks, payment firms and crypto exchanges.More in the glossary failures and suspended part of its business for three months.

We score Coinone 73/100. That puts it above Upbit (68), which has lost money to hackers twice, and Bithumb (58), and below Kraken.

Who runs Coinone?

The exchange is run by Coinone Inc. (주식회사 코인원), founded in February 2014 and based in Yeouido, Seoul's financial district. Its controlling shareholder is The One Group, and the game company Com2uS Holdings appears as a related party in its accounts. Coinone is one of Korea's four big won exchanges with Upbit, Bithumb and Korbit, and works with KakaoBank for real-name won accounts.

No wallet hacks on record

Korean exchanges have a poor security history; Upbit and Bithumb have both lost large sums from hot walletsHot walletA crypto wallet connected to the internet, such as an app or an exchange's online wallet. It is convenient, but more exposed to hacking.More in the glossary. We found no comparable incident at Coinone. The closest is from April 2021, when about 20 people, most of them Coinone customers, woke up to find their coins sold and the money withdrawn. Coinone said its systems had not been breached and that the likely cause was smishing or users without OTP. Victims said similar cases had been happening for two months without any warning from the exchange.

That is account takeover, not a platform hack, and it is the main risk for any exchange customer. It keeps Coinone's security score high but below 90, because a dozen years without a reported breach is good evidence, not proof.

What Korean law protects

The Virtual Asset User Protection Act has applied since 19 July 2024. It requires exchanges to keep customer cash at a bank, separate from their own money, to hold at least 80% of customer coins in cold walletsCold storageKeeping crypto keys on a device or medium that is not connected to the internet, which protects them from most online attacks.More in the glossary, to hold the same coins in the same amounts that customers own, and to set aside a reserve or buy insurance against hacks and outages.

Coinone's 2025 audit report shows how that works in practice:

Item	End of 2025
Customer won at KakaoBank	183.3 billion won
Customer crypto held	About 2.74 trillion won
Bitcoin held for customers	7,845 BTC
User protection reserve	30 billion won
Hack insurance	None listed

The reserve covers about 1% of customer crypto. That would handle a hot-walletHot walletA crypto wallet connected to the internet, such as an app or an exchange's online wallet. It is convenient, but more exposed to hacking.More in the glossary theft of the size Upbit suffered, but not a large cold-wallet loss.

Audited accounts instead of proof of reserves

Coinone does not run a Merkle-treeMerkle treeA way to combine many records into one short code, so that each person can check their own record is included without seeing anyone else's.More in the glossary proof of reservesProof of reservesA report in which a crypto exchange shows that it holds enough coins to cover all customer balances, ideally checked by an outside firm.More in the glossary where you can check your own balance, the way Kraken does. What it has is better than many exchanges offer: audited annual accounts filed with the Financial Supervisory Service and public on DART, with the customer coin holdings listed coin by coin. Anse Accounting Corporation gave a clean opinion on the 2025 figures. The auditor is much smaller than the Big Four firm that audits Upbit, which is why reserves score a little lower.

The 2026 FIU sanctions

Korea's Financial Intelligence UnitFinancial intelligence unitA national government agency that receives reports of suspicious transactions from banks and crypto firms and analyses them for money laundering.More in the glossary inspected Coinone from 21 April to 16 May 2025. It reported about 90,000 breaches of the anti-money-launderingAnti-money launderingThe rules and checks that stop criminals from moving illegal money through banks, payment firms and crypto exchanges.More in the glossary law:

• 10,113 crypto transfers with 16 foreign exchanges that were not registered in Korea, despite FIU letters in 2022 and 2023 telling exchanges to stop;
• about 40,000 failures in customer identity checks;
• about 30,000 cases where transactions were not blocked as the law requires, for example after a customer's periodic re-verification had lapsed.

On 13 April 2026 the FIU barred new customers from moving crypto in or out from 29 April to 28 July, set a 5.2 billion won fine and issued a reprimand to the chief executive. Coinone said it took the decision seriously and would consider its options, including a lawsuit. No customer money went missing, but this is a weak record for a regulated exchange.

How to use Coinone more safely

1. Turn on OTP in an authenticator app, not SMS, and treat any call or text claiming to be from Coinone, the police or the FSS as fraud until you check it yourself.
2. Register withdrawal addresses in advance and test with a small amount.
3. Keep long-term holdings in your own wallet. No exchange reserve covers everything.
4. If you plan to move coins abroad, check that the receiving exchange is registered in Korea. Coinone blocks transfers to unregistered ones.

How we scored it

Security history (85) is Coinone's strongest factor, with no known theft from its wallets. Legal record (58) is the weakest because of the 2026 FIUFinancial intelligence unitA national government agency that receives reports of suspicious transactions from banks and crypto firms and analyses them for money laundering.More in the glossary fine and partial suspension. Reserves (75) and custody (75) reflect audited filings and Korea's bank-custody and cold-storage rules.