Prediction Markets Weekly Digest: June 29 to July 5

Polymarket had its biggest headline yet, a reported $1 billion in annualized revenue, and its worst, a $3M front-end hack, in the same seven days. Three things to watch as the knockouts begin: Brazil vs Japan on June 29, whether Bitcoin dips to $57,500 by July 1, and whether Claude Fable 5 returns to US users on that same deadline.

What resolved last week

Last week ran through the World Cup. This section tracks the upsets – markets where the winning side was a long shot at the start of the week, priced under 35% seven days out, then won anyway. We try to keep sport in the minority, but this week only one non-sports market cleared that bar, so the board leans to the pitch.

POLITICS

Starmer Out by June 30

A week before the deadline, the market gave Keir Starmer leaving office by June 30 just 20%. He was gone by the time it closed. The $7.9M contract spent most of the week as a long shot before reality caught up.

SPORTS

England Held by Ghana

The loudest miss came from the pitch. A draw between England and Ghana was a 16% call a week out, and Ghana delivered it – erasing the $16.5M backing an England win, the most expensive upset of the week.

Ecuador Stun Germany

Ecuador were a 20% shot to beat Germany a week out. They did it anyway on June 25, on $10.7M in volume – one of the tournament’s heavyweights taken down by a side the market had written off.

Colombia Hold Portugal

The weekend kept it going. A draw between Colombia and Portugal was a 26% call seven days out, and it landed on June 28, on $3.5M. Portugal could not break down a side the market expected them to beat.

Trending markets resolving this week

Whale moves and big plays

Two six-figure World Cup positions stood out on Polymarket last week, both flagged by on-chain trackers, neither tied to a public name – and both undone by the same thing.

Unknown whale – Polymarket – Paraguay vs Australia

On June 26, a single $234,000 bet landed on Australia to beat Paraguay, bought at an implied 78%, per Catcher Predict’s on-chain monitoring. The match finished level. A draw the market barely entertained wiped out a heavy stake on the favorite, and with no public wallet the motive stays a guess.

Unknown whale – Polymarket – Japan vs Sweden

The same week another trader put $112,000 on Japan to beat Sweden at an implied 56%, again via on-chain tracking. That match also ended in a draw. Two whales, two favorites, two draws – six figures of conviction undone by the result the top of the book never wanted.

⚠️ Predictionist Tip: Whale size is not whale accuracy. Both of these six-figure bets backed the favorite and still lost, so read a big public position as one data point, not a signal to copy. With copy-trading you inherit the misses, not just the wins.

Prediction market industry news

Polymarket’s Annualized Revenue Crosses $1 Billion

I did not expect this number so soon. Polymarket‘s annualized revenue has reportedly crossed $1 billion, according to CNBC, and it lands as the platform leans into its Commodity Futures Trading Commission (CFTC)-regulated US exchange. To me, a billion-dollar run-rate is the clearest sign yet that prediction markets have moved from crypto curiosity to real financial infrastructure.

A $3M Supply-Chain Hack Hits Polymarket Users

I was less impressed by the platform’s other headline this week. A supply-chain attack drained about $3 million from users after a third-party vendor’s code was compromised and used to inject malicious scripts into the site’s frontend, per The Next Web. Polymarket says it contained the breach and will refund affected users in full. What strikes me is the vector – not the blockchain or the contracts, but a dependency in the web stack, the kind of risk every frontend-heavy exchange now carries.

Kalshi’s Open Interest Sets a $1.16B Record

I keep coming back to one Kalshi number. Its open interest – the value of positions held open, not just traded – hit a record $1.16 billion last week, a first over the billion-dollar mark, driven by the World Cup, per FinanceFeeds. I read that as more telling than raw volume. When traders hold World Cup positions instead of flipping them, that is conviction parked in the market, not churn.

Quick answers

Who is favored in Brazil vs Japan? Will Bitcoin dip to $57,500 by July 1? When could Claude Fable 5 return for US users? Who pulled off the biggest World Cup upset last week? Who leads the World Cup winner market? What was the biggest prediction-market story this week?