Company Upbit, Company Bithumb and Company Coinone Suspend FLOW Deposits and Withdrawals Amid Security Review

In a coordinated move on March 21, 2025, Company Upbit, Company Bithumb and Company Coinone announced the temporary suspension of all deposits and withdrawals for the Flow token while they conduct an urgent security review. The exchanges made clear that spot trading for FLOW pairs remains operational on their order books, but any on-chain movement to or from user wallets is currently blocked. This partial freeze has immediate implications for traders, holders and the broader market.

The market reaction was swift: the price of Flow fell roughly 7% across global markets after the announcement, while trading volume for FLOW pairs on the affected Korean exchanges dropped by over 60%. Importantly, major global platforms such as Company Binance and Company Kraken continue to process FLOW transactions normally, underscoring that this is a localized exchange-led intervention rather than a network-wide outage.

To understand the background, it is essential to note that Flow is a proof-of-stake blockchain developed by Company Dapper Labs, designed for high-throughput NFT and gaming use cases and used by projects like Company NBA Top Shot and Company UFC Strike. While the Flow ecosystem has historically maintained strong security, the network and associated smart contracts have experienced incidents in the past, such as a 2023 third-party marketplace exploit. The current exchange suspensions appear to be a precautionary measure triggered by an identified vulnerability or anomalous activity rather than an admission of a proven breach of exchange hot wallets.

The regulatory context in South Korea is relevant to this coordinated action. Under the country's Company Financial Services Commission (FSC) oversight and the Virtual Asset User Protection Act enacted in 2024, exchanges are required to maintain heightened monitoring, reserves and to report suspicious activity promptly. Past precedents include multi-exchange interventions related to WEMIX and other tokens, often following advisories from industry groups such as the Company Digital Asset Exchange Association (DAXA).

Expert commentary highlights the rationale for suspensions: when anomalies are detected, isolating an asset is a primary risk management tool. As Ms. Mina Choi, a blockchain cybersecurity researcher at Seoul National University, notes, such actions are intended to protect exchange infrastructure and user funds while investigators determine if issues stem from the core protocol, smart contracts, or exchange wallet/address management. Investigations can vary in length from 48 hours to multiple weeks depending on complexity.

For holders and traders on the impacted platforms, the suspension has practical effects: users cannot withdraw FLOW for staking or arbitrage, and cross-exchange strategies are interrupted. Exchanges maintain that account balances remain secure during the freeze. Users are advised to monitor official exchange channels and be vigilant for phishing attempts, which commonly spike during such incidents. Historically, full services resume after fixes—often involving node updates, wallet software patches or changes to deposit address generation processes.

From a market-structure perspective, this event highlights several lessons: the continued importance of decentralized custody for risk-sensitive users, the role of exchange surveillance in maintaining systemic integrity, and how national regulation can drive coordinated actions across major platforms. The outcome of the investigation will be watched closely as it may set further precedent on how exchanges handle perceived network-level risks and coordinate with regulators and blockchain maintainers.

Key takeaways: deposits and withdrawals for FLOW are suspended on three major Korean exchanges; spot trading remains available; FLOW price and local volumes declined sharply; the suspension likely reflects a precautionary security review within a stringent Korean regulatory framework. Stakeholders should follow official statements from Company Upbit, Company Bithumb and Company Coinone and exercise caution against unsolicited withdrawal offers.