Japan’s largest registered cryptocurrency exchange, Bitbank, has issued a stern warning to its users: accessing prediction market platforms like Polymarket could result in full account suspensions. The notice, published on Monday, June 15, 2026, marks one of the first explicit crackdowns by a regulated crypto exchange on prediction market activity in Japan.
For crypto traders in Japan, this is a major development. Bitbank isn’t just cautioning users—it’s threatening to freeze accounts, block trading, and deny access to deposits and withdrawals for anyone linked to prediction markets.
What Bitbank Actually Said
In its official compliance notice, Bitbank made several critical points: “We may restrict accounts making deposits or withdrawals connected to prediction market services.”
Which Platforms Are Targeted
- Polymarket (named explicitly as the primary compliance risk)
- Any platform allowing users to bet on election results, sports outcomes, or future events for financial gain
Legal Basis
Bitbank cited Japan’s gambling laws, stating that using prediction markets for profit while in Japan could be considered illegal gambling. Notably, Japan has not issued formal guidance specifically on prediction markets, but this is taking a cautious approach. As regulators tighten oversight of crypto platforms, digital identity on the blockchain could play a larger role in ensuring compliance while preserving user privacy.
Consequences for Violators
Accounts suspended by Bitbank will lose access to:
- Account logins
- Deposits and withdrawals (crypto and Japanese yen)
- Crypto trading
- All other exchange services
The exchange also added a stark disclaimer: “We will not be liable for any damages incurred by our customers as a result of the account suspension measures.”
Why Prediction Markets Are Now a Problem
Prediction markets let users bet on real-world outcomes using cryptocurrency. Popular platforms include:
| Platform | What You Can Bet On |
|---|---|
| Polymarket | Elections, sports, crypto prices, pop culture |
| Kalshi | US economic data, political events |
| Crypto.com Predictions | Sports, financial markets |
These platforms operate largely from outside Japan, but Bitbank’s warning makes it clear: accessing them from within Japan for financial gain could violate gambling laws.
The Gambling Law Connection
Under Japanese law, most forms of gambling are prohibited except for specific exceptions (like public horse racing or pachinko). Bitbank is now treating prediction markets as unlicensed gambling operations, even if they’re based overseas.
How Bitbank Will Detect These Transactions
it didn’t specify exactly how it will identify Polymarket-linked transfers. However, the notice suggests it may screen for:
- Deposits originating from prediction market wallets
- Withdrawals sent to prediction market platforms
- Suspicious transaction patterns linked to known prediction market addresses
The exchange reserves the right to suspend accounts if it suspects a connection to prediction market services, even without definitive proof.
This Is a First for Japan’s Crypto Industry
Bitbank’s action represents a significant shift in how Japanese crypto exchanges are handling prediction markets:
Key Milestones
- First regulated exchange to explicitly screen for and restrict prediction-market flows
- Happening the same week as similar actions by Kalshi, Crypto.com, and Polymarket themselves regarding state-level financial constraints
- One of the strongest positions taken by a Japanese exchange against prediction market activity
This move comes amid growing regulatory pressure on crypto exchanges in Japan. Earlier in 2024, the Japan Financial Services Agency (FSA) warned five foreign exchanges (KuCoin, Bybit, MEXC, Bitget, Bitcastle) for operating without registration.
What This Means for Japanese Crypto Users
For Active Prediction Market Traders
If you’re using Polymarket or similar platforms from Japan:
- Stop transferring funds through Bitbank immediately
- Consider using non-custodial wallets or exchanges without such restrictions
- Be aware that other exchanges may follow Bitbank’s approach
For Casual Users
- If you’ve never used prediction markets, you’re likely unaffected
- The warning targets users accessing these platforms from Japan
For the Entire Crypto Community
- This sets a precedent for how regulated exchanges handle prediction markets
- May signal tighter compliance ahead for offshore crypto services operating in Japan
Bitbank’s Official Stance
The exchange framed this decision as: “A commitment to comply with relevant Japanese regulations and to ensure a secure trading environment.”
Bitbank also urged customers to:
- Exercise caution when using external services
- Avoid involvement in criminal activity or legal disputes
The Bottom Line
Bitbank isn’t banning prediction markets globally—it’s protecting itself from potential legal liability under Japanese gambling laws. By threatening account suspensions, the exchange is making it clear that using offshore prediction markets for profit from Japan is a compliance risk.
For Japan’s crypto users, this is a wake-up call. Prediction markets may be legally gray or outright prohibited, and regulated exchanges like Bitbank won’t risk their licenses by allowing fund flows to these platforms.
As prediction markets continue growing globally, more countries may follow Japan’s cautious approach. The question isn’t whether Bitbank made the right move—it’s whether other exchanges will follow.
