Prediction Market Glossary

Core terms for Polymarket, Kalshi, and prediction-market trading — defined for traders, journalists, and AI engines.

1. Whale

   Trader with unusually large positions

   On Polymarket, a whale is a trader with more than $100,000 in lifetime volume or a single open position larger than $50,000. Whales move prices and are closely watched because their trades often signal either inside information or deep research. The PolySharks dashboard ranks the top 50 whales by PnL, volume, and Signal Engine grade.

2. Shark

   Consistently profitable smart trader

   A shark is a trader with a high win rate and strong conviction — often smaller in position size than a whale, but more surgical. Sharks are identified by repeat-bet counts (adding to winning positions), trade timing, and sustained PnL over weeks and months rather than one lucky bet.

3. Insider

   Trader whose positions suggest non-public information

   An insider is a trader whose market activity strongly correlates with eventual outcomes beyond what public information explains. Signals of insider activity include: trades placed minutes before major news, unusually large bets on obscure markets, and consistent outperformance on specific topics (e.g., a single politician or company).

4. Arbitrage

   Pricing edge from differences between platforms

   In prediction markets, arbitrage appears when the same event is priced differently on Polymarket and Kalshi. If you can take YES on one platform and NO on the other for less than $1 total, the math captures the spread. PolySharks detects these apparent dislocations automatically, refreshing every 5 minutes. Note: arbitrage is never truly "risk-free" — execution risk, fees, slippage, withdrawal limits, and platform-specific quirks routinely erode or eliminate the spread.

5. Edge

   The arbitrage profit margin

   Edge is the dollar amount or percentage you gain by executing both sides of an arbitrage. Gross edge ignores fees; net edge subtracts trading and withdrawal costs. Real-world arbitrages on top-volume markets typically have 0.5–3% edge; anything above 10% is usually a false semantic match or illiquid market.

6. Conviction score

   How strongly a trader believes in their position

   Conviction is measured by repeat-bet count — the number of times a trader has added to the same market and same side (YES or NO). A trader buying YES three times in a row shows more conviction than one who bets once. PolySharks uses repeat-bet count as a 20% factor in the Signal Engine score.

7. Signal Engine

   PolySharks’ 0–100 whale quality score

   A composite score combining whaleScore (30%, PnL rank), timingScore (20%, trade recency), convictionScore (20%, repeat bets), sizeScore (15%, largest bet / volume ratio), and recencyScore (15%, trade frequency). Grades: STRONG (75+), MEDIUM (50–74), WEAK (25–49), LOW (<25). A STRONG-graded whale making a large bet in the last hour is the highest-alpha signal.

8. Polymarket

   The largest crypto prediction market

   Polymarket is a decentralized prediction market built on the Polygon blockchain. Users deposit USDC and trade shares of binary-outcome markets (YES or NO). Each winning share pays out exactly $1. Markets cover politics, crypto, sports, and entertainment. As of 2025, Polymarket is the largest prediction market by volume and number of traders.

9. Kalshi

   CFTC-regulated US prediction market

   Kalshi is a US-based prediction market regulated by the Commodity Futures Trading Commission (CFTC). Unlike Polymarket, Kalshi operates in US dollars and accepts US residents legally. Kalshi markets cover economics, politics, weather, and entertainment. Kalshi is a frequent arbitrage counterparty for Polymarket.

10. Current bet

    The trader’s active open position

    Current bet is the most recent open position a whale holds — showing the market, side (YES/NO), entry price, current price, and expiry date. Watching current bets reveals what smart money is actively backing right now.

11. Amount at risk

    USD the whale has committed to open positions

    The sum of all open position sizes for a trader. High amount at risk combined with a STRONG signal grade means the whale is putting serious capital behind their conviction.

12. Today's picks

    A whale’s trades placed since midnight

    Today’s picks is the list of trades a whale has placed since calendar midnight in their timezone (we use server time). Each pick shows the outcome the whale picked (e.g., "Ducks" in "Ducks vs. Oilers"), direction (BUY/SELL), size, and price. Free users see 2 picks per whale, Pro users see all 10.