Whale Watch

Large Kalshi and Polymarket trades matched to the best retail price still available. In build.

Coming soonIn build on the tested engine

What it does

Coming soon Whale Watch is in build. Kalshi and Polymarket publish their trades. Whale Watch will pick out the large ones, map them to the game and side, and show where you can still bet that side at a better price.

The rule that matters: a big trade only counts if it was filled at a price the same as or worse than the best price still available elsewhere. Someone paying more than you'd have to pay is a stronger signal than someone who got a better price than is on offer now.

Planned: the whale total behind each side, the individual fills, the edge of the best available price against that volume-weighted price, Where to bet with every venue on both sides net of fees, and a running record of every signal, wins and losses.

Who it's for

Bettors who use prediction markets and want to see where the size is going.
Anyone who uses large money as context for a price, not as a blind signal.
Bettors who track closing-line value and want to see which side the size took before the close.

Coverage

Trades: Kalshi and Polymarket public trade feeds. These are exchange trades, not sportsbook handle; nobody publishes sportsbook bet-by-bet data.

Where to bet: every book in the collector, with exchanges and prediction markets at their net price after fees and offshore books shown for comparison only.

Sports the collector is built for: NFL, college football, CFL, NBA, WNBA, college basketball, NHL, MLB, KBO, NPB and soccer (Premier League, MLS, La Liga, Bundesliga, Serie A, Ligue 1, Champions League). What you see on a given day depends on what is in season and what the books have posted.

What to check before you bet

Whether the trade could be a hedge. One large trade can be one side of a bigger position elsewhere.
The edge of the price you can actually get, not the whale's price.
Fees on both the whale's venue and yours.
The signal's record over time, not one result.

How it will work

Planned: open Whale Watch and set the minimum trade size.
Each card will show the whale total, the side, and the best price still available.
Open a card for the fills and the Where to bet table.

Whale Watch is in build

The engine math behind it already exists and is tested. The app shows a preview of what is coming.

See the preview How to use it

Frequently asked questions

Where does whale data come from?

From Kalshi's and Polymarket's public trade data. It's exchange trading, not sportsbook handle.

Does following whales win?

We make no such claim. Every signal will be logged and graded publicly, so you can judge the record yourself.

Is it live?

Not yet. It's in build.

Is it free?

During launch the market tools are free with a free account: sign in with Discord. The calculators and the Learning Center are always free and need no account.

Free calculators for this

Expected value (EV) calculatorEV, edge and Kelly from a fair %, fair odds or a two-sided market with the vig removed.Exchange and prediction-market fee calculatorNet price after Kalshi, Polymarket, ProphetX, Novig and exchange fees.

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