Worldwide search interest in prediction markets has returned to roughly where it sat before the 2026 World Cup, and the two venues that take almost all the category’s trading volume are moving apart as it does.
Both peaks in Google’s data land on tournament dates. The decline since is a return to the pre-tournament baseline. What has changed underneath is the split between the leaders: Kalshi’s monthly volume is pacing roughly 15% below its July record, while Polymarket’s has halved since June. Polymarket still leads on social mindshare.
On Google Trends’ worldwide weekly series for the search term “prediction market,” the index hit its five-year high of 100 in the week of June 7-13, 2026. It read 17 in the week of Aug. 9-15, the most recent complete week — 83% below the peak. The current week, Aug. 16-22, reads 16, and Google flags that point as carrying incomplete data.
A trader posting as Goaty wrote Monday that interest was “down 85% from its all-time high” and that “the global prediction market hype is over.” The 85% figure uses the partial week.
The Football Calendar
The 2026 World Cup opened June 11 at Estadio Azteca in Mexico City, inside the week that set the five-year high. Interest stayed elevated for the length of the tournament: 85 in the week of June 14-20, 92 in the week of June 28-July 4, 57 by July 12-18.
Narrowing the window to daily resolution moves the peak to a single date. In a May 1 to Aug. 17 daily series, the index hit 100 on July 19, the day Spain beat Argentina 1-0 at MetLife Stadium in the final. It read 7 on Aug. 16.
The trading data followed the same calendar. The Defiant reported in June that Polymarket’s World Cup winner markets had crossed $1.8 billion in volume as the group stage opened.
Record July, Slower August
Prediction-market volume across all venues DefiLlama tracks reached $17.27 billion in July, the highest month on record, after $14.78 billion in June and $10.64 billion in May. Through Aug. 17, the category has done $7.83 billion, a pace of about $14.3 billion for the full month — roughly 17% below July and about 34% above May.
DefiLlama’s headline volume figure is cash volume, or contracts multiplied by the price paid, not notional. Kalshi’s 30-day notional volume is $36.74 billion against $11.02 billion in cash volume, so the two measures differ by more than three times. Comparisons here use cash volume throughout. Kalshi also sits in DefiLlama’s prediction-market category despite being a CFTC-designated contract market with no onchain footprint and no TVL entry.
The Defiant reported a comparable cooldown in February, when monthly volume dipped for the first time since August 2025.
Kalshi’s Widening Lead
Kalshi did $9.40 billion in June and $12.37 billion in July, its record month. Through Aug. 17 it has done $5.73 billion, a pace of about $10.45 billion.
Polymarket went the other way. It did $4.29 billion in June, $3.68 billion in July and $1.18 billion through Aug. 17, a pace of about $2.14 billion — half its June total.
The ratio between them has widened each month: Kalshi did 2.2 times Polymarket’s volume in June, 3.4 times in July and 4.9 times so far in August. Over the past seven days, Kalshi took 77.4% of the category’s $3.20 billion in volume and Polymarket 16.8%, leaving 5.8% for every other venue DefiLlama tracks.
Both have raised comparable sums. Polymarket has taken $2.88 billion, ahead of Kalshi’s $2.69 billion, per DefiLlama. Kalshi’s open interest is $811.46 million against Polymarket’s $345.07 million.
The Defiant first reported Kalshi’s weekly volume passing Polymarket’s in December, when the margin was 92%.
Mindshare Versus Order Flow
The mindshare data shows a far closer race. Figures from social analytics firm Moni, posted Monday by a trader using the handle ih8y, put Polymarket at 21.57% of prediction-market mindshare against Kalshi’s 20.8%, with Polymarket marked down 10.22% and Kalshi up 4.02%. The difference between the two is 0.77 percentage points.
The shares come from a screenshot of Moni’s product. Moni says it tracks 15,000 hand-curated crypto accounts.
Third place on the same board is Wintermute at 4.98%, up 2.55%. The market maker began quoting two-sided markets on Polymarket and Kalshi in May. Jupiter is at 4.31%, predict.fun at 2.88% and Kalshi’s separate crypto account at 2.99%.
TVL Keeps Draining
Capital parked in onchain prediction markets has fallen every month since April. Category TVL was $576.52 million at the end of April, $537.07 million in May, $520.88 million in June, $404.78 million in July and $403.73 million now — down 30% from the April figure across a stretch when monthly volume rose 61% to July’s record.
Polymarket’s own TVL is $343.82 million, and it recorded 52,173 active addresses over the past 24 hours. Research covering 2.5 million wallets earlier this year found 84% of Polymarket traders were losing money, with 2% ever clearing $1,000 in profit.
