BigBoss has promised full compensation, including bonus credit, to customers who suffered unauthorized transactions or other losses while using copy trading through a MASS Account, adding a new layer of customer remediation following the cyberattack on Japanese internet infrastructure provider GMO Internet.
In its third customer update, published on October 27, the forex and CFD broker instructed affected customers to contact its support team so their trading activity could be reviewed and compensation processed. BigBoss said it would examine relevant transactions following each inquiry and promptly initiate the compensation procedure.
The announcement is significant because it goes beyond the broker’s previous guidance, which directed customers toward GMO Internet’s own compensation arrangements. However, BigBoss has not yet published detailed eligibility rules, a claims deadline, a payment schedule or a breakdown of the losses covered by its promise.
The commitment also applies specifically to customers who used copy trading through a MASS Account. It should not be interpreted as a blanket compensation guarantee covering every BigBoss customer or every loss associated with the wider incident.
BigBoss expands its response to the cyberattack
The compensation announcement follows a series of updates tracing the disruption back to GMO Internet’s Onamae.com Desktop Cloud service, a virtual server platform used by traders to operate trading software remotely.
GMO began investigating on October 19 after receiving customer inquiries. On October 20, it identified a malicious program in some customer server environments. The company began shutting down affected service infrastructure on October 21 to prevent further damage and published its initial incident notice that day.
The security incident subsequently developed into a financial concern for brokerage customers. GMO confirmed that unauthorized access had occurred, customer information had been taken outside the company and some users had reported transactions in their trading accounts that they did not recognize.
GMO’s earlier investigation identified 26,739 potentially affected server environments. That figure represents the potential scope of exposure, not the number of servers confirmed to have been compromised or the number of brokerage accounts subjected to unauthorized trading.
BigBoss issued its initial notice on October 21, warning customers about the incident and recommending immediate security measures. Its second update, published on October 26, referred customers to GMO’s compensation announcement and directed them to the service provider for further information about the process.
The October 27 update marks a meaningful change in the broker’s position. Rather than simply directing customers to GMO, BigBoss has now explicitly committed to compensating eligible MASS Account copy-trading customers for unauthorized transactions or other losses resulting from the incident.
The announcement does not establish how many BigBoss customers were affected, the total value of disputed transactions or whether the broker has completed any compensation payments. It also does not confirm that BigBoss’s own systems were breached. The disclosed incident originated in third-party infrastructure used by traders.
How BigBoss’s promise compares with GMO’s compensation framework
GMO announced its own compensation framework on October 24, covering realized trading losses attributable to unauthorized transactions that the company confirms resulted from the incident.
Under that framework, eligible losses include trading losses, fees and similar costs associated with confirmed unauthorized transactions. GMO explicitly excludes losses caused by market fluctuations, profits customers could have earned from transactions and other indirect damages.
GMO also established an individual assessment process. Customers may need to provide information demonstrating the date, details and financial impact of disputed transactions. The company said it would examine transaction records, access logs and other supporting materials before notifying customers of its decisions.
Its framework separately provides a JPY 5,000 goodwill payment to every customer currently using Onamae.com Desktop Cloud, regardless of whether that customer suffered a financial loss. The payment is distinct from compensation for unauthorized trading losses.
GMO said it would announce the detailed application procedure, required documentation, application period and payment schedule by November 6. Its framework also provides for coordination with brokers: where a broker issues a refund, GMO’s payment is reduced by the amount refunded, preventing duplicate compensation for the same loss.
BigBoss’s wording raises an important question. Its commitment to provide full compensation, including bonus credit, for unauthorized transactions or other resulting losses could potentially offer affected customers a different or broader remedy. However, the announcement does not explain whether the broker will cover loss categories excluded by GMO, apply the same evidence requirements or use a separate calculation method.
The reference to bonus credit introduces another unresolved issue. BigBoss has not explained whether compensation will be provided entirely as account credit, partly in cash or through a combination of payment methods. Nor has it specified whether any bonus component will carry trading, withdrawal or expiry restrictions.
Until the broker publishes these details, customers should not assume that its promise automatically overrides GMO’s exclusions or guarantees reimbursement for unrealized losses, foregone profits or indirect financial consequences.
GMO reports publication of alleged customer information
The compensation developments come as the underlying incident continues to evolve. On October 27, GMO reported that individuals believed to be the attackers had published information they claimed related to the company and its customers.
In an update issued at 13:55 Japan time, GMO said it was verifying the published material and warned that it could contain information inconsistent with the facts. The company also said that a ransomware attack had not been confirmed as of that update.
GMO subsequently warned customers against accessing or circulating the alleged information, stating that information about people who visited the relevant site had also been obtained by the attackers. The company said it was cooperating with police and other relevant authorities and cautioned customers against suspicious communications exploiting the incident.
The latest developments increase the importance of separating confirmed findings from unverified claims. The publication of purported customer information does not establish that every account was compromised, that all circulating material is authentic or that every customer experienced financial losses.
It does, however, create additional concerns about phishing, impersonation and fraudulent recovery offers targeting worried customers. Anyone seeking compensation should use established support channels and avoid sharing passwords, authentication codes or sensitive account credentials with unsolicited contacts.
The incident has already affected other brokerage operations. DaveFinances has reported on GMO Internet’s shutdown of its FX trading VPS, which interrupted a service used by traders running automated strategies. Separate coverage documented AvaTrade Japan’s confirmation of unauthorized customer trades and OANDA Securities Japan’s temporary withdrawal delays following the security incident.
These developments demonstrate that a compromise at a third-party infrastructure provider can create consequences across several brokerage businesses, even without evidence that each broker’s own systems were penetrated.
What customers and the industry should watch next
BigBoss’s compensation commitment is a potentially important step toward restoring customer confidence, but the strength of the promise will ultimately depend on how it is implemented. Customers need a clear process for identifying eligible transactions, submitting evidence, understanding compensation calculations and receiving payment.
The most important outstanding questions concern the number of affected MASS Accounts, the aggregate value of unauthorized transactions, the distinction between realized and unrealized losses, and whether bonus credit will be treated as equivalent to cash compensation.
BigBoss should also clarify how its process interacts with GMO’s framework. If a customer seeks reimbursement from both parties, the handling of refunds, overlapping claims and disputed eligibility could determine how much compensation is ultimately received and how quickly the claim is resolved.
The incident also highlights the importance of third-party security controls in leveraged trading. A remote server used to operate MetaTrader software can become part of a trader’s account-security chain when login credentials or other sensitive information are stored in that environment. Brokers and infrastructure providers therefore need clear procedures for investigating suspicious trades, preserving evidence and coordinating customer remediation.
For the data-security side of the incident, Japan’s Personal Information Protection Commission publishes guidance on responding to personal-data leaks, including reporting and response procedures for qualifying incidents. That framework provides regulatory context for data exposure, but it does not determine BigBoss’s contractual compensation obligations or settle the allocation of trading losses between the broker and GMO.
For customers, the immediate priority is to review account history, identify transactions they did not authorize, preserve relevant records and contact BigBoss through official support channels. For the industry, the next test is whether the broker turns its broad compensation promise into a transparent and consistently applied claims process.
BigBoss has now moved beyond referring customers to GMO’s compensation announcement. Whether that commitment delivers a materially broader remedy remains unresolved. The decisive evidence will be the published eligibility criteria, the treatment of bonus credit, the scope of covered losses and the outcomes of individual claims.
Johan Shamshad is a financial markets writer at Dave Finances covering cryptocurrencies, trading platforms, brokers, fintech, financial regulation, and developments across global markets. He previously worked at Gulf News, adding newsroom experience to his coverage of fast-moving financial and digital-asset markets.
His work focuses on identifying market-moving events, company developments, regulatory changes, product launches, and shifts in trading and financial infrastructure.
Johan contributes news and analysis designed to help readers understand not only what happened, but why a development matters and how it may affect the wider financial landscape. You can reach out to him via his social media accounts:
Linkedin: https://www.linkedin.com/in/johan-shamshad-742851262/
X: https://x.com/Yasmine_FX
Investing: https://www.investing.com/members/contributors/279781574