The same event — "Will Bitcoin exceed $100k by March 2026?" — can be listed on multiple prediction market platforms simultaneously. Each platform has its own order book, its own traders, and its own pricing.
When the combined cost of buying opposite outcomes across two platforms is less than $1 (the guaranteed payout), the difference is locked-in profit regardless of the outcome. This is cross-platform prediction market arbitrage.
This post breaks down how it works in practice, what to watch out for, and what realistic returns look like.
How It Works
Example:
- Polymarket: YES = $0.63
- Opinion Trade: NO = $0.34
- Total cost: $0.97
- Guaranteed payout: $1.00
- Profit: $0.03 per share pair (3.1%)
You buy YES on Polymarket and NO on Opinion Trade. One side must win. You get $1 back. You paid $0.97. The $0.03 spread is yours — regardless of the actual outcome.
This isn't a prediction or a directional bet. It's capturing a pricing discrepancy between two independent markets.
Why Do Prices Diverge Between Platforms?
Prediction markets don't share order books. Each platform prices events independently based on its own supply and demand dynamics. Several factors create and sustain these price differences:
Different User Bases and Behavior
Polymarket has grown into a mainstream platform with deep liquidity across politics, crypto, sports, and world events. Opinion Trade is a growing BSC-based platform with its own active trader community. These user bases don't fully overlap — they interpret news differently, react at different speeds, and carry different biases. When one group trades aggressively on a piece of news, the other platform may not move at all for minutes or hours.
Cross-Chain Friction
Polymarket runs on Polygon (USDC). Opinion Trade runs on BSC (USDT). Moving capital between them requires bridging across chains, which takes time and costs fees. This friction prevents prices from converging quickly. In traditional finance, arbitrageurs can move money near-instantly — in prediction markets, you might wait 5-30 minutes for a bridge transaction, during which the spread can close on its own.
Limited Cross-Platform Arbitrage Activity
Unlike traditional finance where market makers actively connect fragmented venues, very few traders run cross-platform arbitrage on prediction markets. The infrastructure is mostly manual, capital has to be pre-positioned on multiple chains, and the operational overhead is significant. This means pricing inefficiencies persist much longer than they would in more mature markets.
Emotional and Reactive Trading
Prediction market participants often trade on conviction. A headline or a tweet can move prices 3-7% on one platform while the other barely reacts. These emotional swings create temporary but exploitable spreads.
Conditions for Successful Arbitrage
Every one of these must be satisfied. Missing even one can turn a "risk-free" trade into a loss.
1. Resolution Rules Must Be Identical
This is the most important factor and the one most people overlook.
Both platforms must resolve the market using the same criteria — same data source, same definition of the outcome, same edge case handling. If Platform A resolves based on an "official government announcement" and Platform B uses "Associated Press call," you don't have arbitrage — you have two different bets.
Real risk: A market about whether a political figure will resign by a certain date. One platform counts a verbal statement. Another requires a signed letter. Same event, different resolution logic — and suddenly both sides can lose.
Read resolution criteria on both platforms before entering any position. Word by word. If there's any ambiguity, skip it.
2. Timing and Expiry Must Align
Markets must cover the exact same time window. "Bitcoin above $100k by end of Q1" vs "Bitcoin above $100k by March 31 23:59 UTC" — these might be identical, or they might not.
Different close times, different resolution windows, different grace periods — any mismatch can break the arbitrage.
3. Platform Trust
You're locking capital on two platforms simultaneously. If either platform freezes withdrawals, disputes resolution, or goes down — your risk-free position becomes very risky.
Stick to established platforms with a track record of fair and transparent resolution.
4. Sufficient Liquidity
A 4% spread means nothing if you can only fill 20 shares. Check:
- Order book depth at prices that maintain the spread
- That your order size won't significantly move the price
- Both sides have enough liquidity for your target position
In practice: Most cross-platform arb opportunities support $100-$500 per leg. On major markets you can occasionally get $1,000+. Don't expect to deploy $10k on a single opportunity.
5. Capital Lock-Up
When you buy YES on one platform and NO on another, your capital is locked until the event resolves. This is the hidden cost that makes or breaks the strategy.
A 3% return over 4 months is 9% annualized. The same 3% over 7 days is 156% annualized. Duration matters enormously.
Annualized return = (spread / cost) × (365 / days_until_resolution)
| Spread | Lock-up | Annualized |
|---|
| 2% | 7 days | 104% |
| 2% | 30 days | 24% |
| 2% | 90 days | 8% |
| 3% | 7 days | 156% |
| 3% | 30 days | 36% |
Short-duration arbs are dramatically more valuable per unit of capital.
6. Fees
Fees eat directly into your spread. Understanding the fee structure on each platform is critical.
Polymarket: 0% trading fees on most markets. This is a major advantage for arbitrage.
Opinion Trade: Uses a dynamic fee curve based on probability. The formula is built around price × (1 - price), creating a parabolic structure where fees peak at 50/50 and drop sharply toward the edges:
| Probability | Taker Fee | Why It Matters |
|---|
| 50% | 2.0% | Maximum fee — worst case for arb |
| 30% or 70% | 1.7% | Still significant |
| 10% or 90% | 0.7% | Much more manageable |
| 5% or 95% | 0.4% | Minimal impact |
| 1% or 99% | 0.08% | Nearly free |
Key insight: On Opinion Trade, always try to be a maker rather than a taker. Makers pay 0% fee. If you must take, positions near the probability edges (below 15% or above 85%) carry significantly lower fees than those near 50/50.
Additional costs:
- Blockchain gas fees: $0.01-$0.50 per transaction
- Bridge fees (Polygon ↔ BSC): 0.1-0.3%
Always calculate net spread after ALL fees before entering a position.
7. Execution Risk
You need to execute both legs close to simultaneously. If you buy one side and the other moves before you can fill, the arb may disappear — or you're left with a naked directional position.
Tips:
- Pre-deposit funds on both platforms
- Use limit orders where possible
- Execute the less liquid side first
- Accept that some opportunities will slip away
Platform Comparison for Arbitrage
The prediction market landscape has expanded significantly. Here's how the main platforms compare from an arbitrage perspective.
Primary Pair: Polymarket ↔ Opinion Trade
This is the most practical cross-platform arbitrage pair available today.
| Factor | Polymarket | Opinion Trade |
|---|
| Chain | Polygon | BSC |
| Currency | USDC | USDT |
| Trading Fee | 0% | 0-2% taker / 0% maker |
| Liquidity | Deep | Growing, thinner on most markets |
| Market Coverage | Politics, crypto, sports, world events | Similar coverage, expanding catalog |
| Resolution | Transparent, reliable track record | Generally reliable on major markets |
Why it works: Zero fees on Polymarket combined with the ability to place as a maker on Opinion Trade (0% fee) means effective fee drag can be near zero. Both platforms list the same major events. The Polygon ↔ BSC bridge infrastructure is well-established.
Main challenge: Bridging time and cost. Capital needs to be pre-positioned on both chains for fast execution.
Alternative Platforms
These platforms expand the arbitrage landscape but each has distinct trade-offs:
| Platform | Chain / Currency | Fees | Best For | Limitations |
|---|
| Kalshi | Centralized / USD | 0.07-1.75% taker | US-regulated markets, institutional trust | Fiat-only — slow bank transfers make fast arb with crypto platforms difficult |
| Limitless | Base / ETH | 0.03-3% adaptive | Short-duration markets (30min, 1hr, daily) | Fees increase as resolution approaches; newer platform |
| Probable | BNB Chain | 0% trading, gas sponsored | Zero-fee arbitrage potential | Launched Dec 2025, limited track record and liquidity so far |
| Predict.fun | BNB / Blast | Taker-only | DeFi yield on collateral while positions are open | Lower liquidity on most markets |
| Myriad | BNB / Abstract / Linea | 3% (AMM) | Multi-chain access | High fees make arbitrage impractical |
| PredictIt | Centralized / USD | 10% profit + 5% withdrawal | Academic research | Fee drag (14% total) kills any arbitrage opportunity |
Cross-Platform Pair Analysis
Not all platform combinations are equally viable for arbitrage. Here's a structured breakdown:
Polymarket ↔ Opinion Trade ✅ Best overall
- Low combined fees (0% + 0% maker)
- Overlapping market coverage
- Established bridge infrastructure (Polygon ↔ BSC)
- Largest number of matching markets
Polymarket ↔ Kalshi ⚠️ Operationally complex
- Both have deep liquidity on US political/economic markets
- The fiat/crypto split is the main obstacle — bank transfers vs crypto means slow capital movement
- Works best if you already have capital pre-positioned on both
- Resolution sources may differ more often than Poly ↔ Opinion
Polymarket ↔ Probable 👀 Worth watching
- Zero fees on both sides would be ideal for arb
- Both crypto-native (Polygon ↔ BNB Chain)
- Probable is very new — liquidity is still developing
- If it scales, could rival Poly ↔ Opinion
Polymarket ↔ Limitless ⚠️ Niche use case
- Both crypto-native, easy bridging (Polygon ↔ Base)
- Limitless' adaptive fees increase near resolution — can eat into short-term spreads
- Interesting for longer-dated markets where the fee stays low
Opinion Trade ↔ Probable 👀 Zero bridge friction
- Both on BNB Chain — no cross-chain bridging needed
- Same-chain execution is a meaningful advantage (speed + no bridge cost)
- Limited by Probable's early-stage liquidity
Any platform ↔ unproven platforms ❌ Avoid
- Counterparty risk outweighs any spread. Not worth it.
Realistic Profitability
Typical Spreads (Polymarket ↔ Opinion Trade)
Being honest about what you'll actually find scanning markets:
- Major markets (US elections, BTC milestones): 0.5-2% gross spread
- Mid-tier markets (Fed decisions, major sports): 1-3% gross spread
- Niche markets (specific policy outcomes, smaller events): 2-5% gross, but thin liquidity
Most of the time, major markets are efficiently priced with spreads under 1%. The better opportunities appear on mid-tier and niche markets, and during fast-moving news events when one platform reprices faster than the other.
After Fees
As taker on Opinion Trade (at 50% probability):
| Gross Spread | Opinion Fee | Bridge | Net Spread |
|---|
| 2% | 2.0% | 0.2% | ≈ 0% (break-even) |
| 3% | 1.7% | 0.2% | 1.1% |
| 5% | 1.3% | 0.2% | 3.5% |
As maker on Opinion Trade (0% fee):
| Gross Spread | Opinion Fee | Bridge | Net Spread |
|---|
| 1.5% | 0% | 0.2% | 1.3% |
| 2% | 0% | 0.2% | 1.8% |
| 3% | 0% | 0.2% | 2.8% |
This is why maker execution on Opinion Trade is critical. It's often the difference between a viable trade and breaking even.
Realistic Expectations
- Conservative (major markets, maker execution): 2-5% monthly on deployed capital
- Active (scanning daily, mixed market tiers): 5-8% monthly
- Aggressive (every opportunity, including niche): 8-12% monthly, but with higher execution and platform risk
Annual range for a disciplined operator: 25-60% on actively deployed capital. This requires daily monitoring, pre-positioned capital on both chains, and careful fee management.
The Compounding Constraint
Cross-platform arb doesn't compound easily. Capital is locked until resolution, sits split across multiple chains, and opportunities are size-limited. This is active work, not passive yield.
Tools and Resources
Having the right tools makes a significant difference in finding and executing arbitrage opportunities.
Arbitrage Scanners
- OplyScan — Cross-platform prediction market arbitrage scanner
- ArbBets — Scans Polymarket, Kalshi, and Opinion Trade for arbitrage opportunities
- Oddpool Arb Dashboard — Real-time arbitrage scanning across Kalshi and Polymarket
Market Data and Analytics
- PolymarketScan — Market data explorer and trader tracking for Polymarket
- Polytrage — Telegram-based real-time arbitrage alerts
Browser Extensions
- PolySniper — Chrome extension for detecting Polymarket arbitrage
Cross-Chain Bridges
Platforms
The Bottom Line
Cross-platform prediction market arbitrage works. The edge exists because most traders don't compare prices across platforms, the infrastructure for cross-chain execution is still manual, and pricing inefficiencies persist longer than they would in more mature markets.
What it requires:
- Resolution rule verification on both platforms — every single time
- Capital pre-positioned on multiple chains
- Daily monitoring for new opportunities
- Fee awareness — especially maker vs taker on Opinion Trade
- Patience — capital is locked until resolution
- Discipline — many apparent spreads disappear after fees
It's not flashy, it's not passive, and it's not free money. But for those willing to put in the operational work, it's one of the more reliable edges available in prediction markets today.
This post reflects practical experience and analysis. Not financial advice. Do your own research and never risk more than you can afford to lose.
