Prediction Markets 2028 Democratic Presidential Nominee

2028 Democratic Presidential Nominee Odds

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Updated 13 minutes ago · 7:44 PM PDT

Gavin Newsom leads the 2028 Democratic nomination at 17.5%, holding frontrunner status off a February book tour that doubled as a campaign prelude and a Guardian quote about "stepping into that void" if no one else brings the fire. Jon Ossoff has a 15.6% chance, still weighing a presidential run against a 2028 Senate primary challenge to Chuck Schumer. Alexandria Ocasio-Cortez rounds out the top three at 15.0% after a recent rally in Augusta where he tore into the "Mar-a-Lago Mafia" over the Iran war, affordability, and corruption. DeFi Rate's custom odds tracker blends live pricing from Kalshi, Polymarket, and Forecastex into a single consensus probability, refreshed hourly.

Largest Spread

2.93%

Mark Kelly → View arbs

Current Favorite

17.5%

Gavin Newsom 17.8%

24H Volume (Share)

$716.4K

Momentum Leader

+12.1%

Jon Ossoff YTD change

Current Odds Snapshot

Current probabilities across platforms with liquidity indicators

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Gavin Newsom

Vol $13.5K Spread 9.5%

Agg 17.5%

↓ -17.8%

California Governor

F 27.0%

P 17.5%

K 17.5%

Jon Ossoff

Vol $18.7K Spread 1.5%

Agg 15.6%

↑ +12.1%

P 16.0%

K 14.5%

AOC

Alexandria Ocasio-Cortez

Vol $35.2K Spread 3.4%

Agg 15.0%

↑ +3.1%

NY Representative

P 15.4%

K 14.5%

F 12.0%

Polymarket 15.4%

Vol $20.8K 15.3–15.4¢

Kamala Harris

Vol $11.4K Spread 1.9%

Agg 7.8%

↑ +3.9%

K 9.5%

F 9.0%

P 7.6%

Mark Kelly

Vol $10.2K Spread 3.1%

Agg 5.7%

↑ +3.9%

K 6.2%

P 3.1%

Pete Buttigieg

Vol $2.3K Spread 8.8%

Agg 5.3%

↑ +0.8%

F 14.0%

K 5.5%

P 5.3%

Josh Shapiro

Vol $1.3K Spread 5.5%

Agg 4.9%

↑ +0.7%

F 10.0%

P 5.0%

K 4.6%

Rahm Emanuel

Vol $12.0K Spread 2.2%

Agg 4.5%

↑ +2.5%

K 4.5%

P 2.4%

Andy Beshear

Vol $545 Spread 6.7%

Agg 3.4%

↑ +0.8%

F 9.0%

K 3.6%

P 2.4%

Wes Moore

Vol $21.3K Spread 3.6%

Agg 2.4%

— +0.0%

F 5.0%

K 2.5%

P 1.5%

Ro Khanna

Vol $10.1K Spread 0.1%

Agg 2.2%

↑ +1.0%

K 2.3%

P 2.2%

James Talarico

Vol $3.3K Spread —

Agg 1.7%

↑ +1.2%

K 1.7%

Kalshi 1.7%

Vol $3.3K 1.6–1.7¢

Jon Stewart

Vol $1.8K Spread 0.9%

Agg 1.4%

↑ +0.5%

Comedian

P 2.0%

K 1.1%

Michelle Obama

Vol $289 Spread 0.2%

Agg 1.2%

↑ +0.2%

K 1.2%

P 1.0%

Gretchen Whitmer

Vol $2.9K Spread 7.1%

Agg 1.1%

↓ -0.7%

F 8.0%

P 1.2%

K 1.0%

JBP

J.B. Pritzker

Vol $1.6K Spread 2.9%

Agg 1.1%

↓ -1.0%

F 4.0%

K 2.6%

P 1.1%

Dwayne Johnson

Vol $2.7K Spread 0.9%

Agg 1.1%

↓ -0.2%

P 1.1%

K 0.2%

Raphael Warnock

Vol $291 Spread 0.0%

Agg 0.7%

↑ +0.2%

K 0.8%

P 0.7%

Cory Booker

Vol $4.8K Spread 0.1%

Agg 0.6%

↓ -0.1%

K 0.6%

P 0.5%

Mark Cuban

Vol $3.9K Spread 0.4%

Agg 0.6%

↓ -0.2%

K 0.9%

P 0.5%

Bernie Sanders

Vol $712 Spread 0.1%

Agg 0.6%

↑ +0.1%

K 0.7%

P 0.5%

Chelsea Clinton

Vol $468 Spread —

Agg 0.5%

— +0.0%

P 0.5%

Polymarket 0.5%

Vol $468 0.5–0.6¢

Elissa Slotkin

Vol $1 Spread —

Agg 0.5%

— +0.0%

K 0.5%

Kalshi 0.5%

Vol $1 0.5–0.6¢

Hunter Biden

Vol $1.4K Spread 0.0%

Agg 0.5%

— +0.0%

K 0.5%

P 0.5%

Roy Cooper

Vol $37 Spread 0.2%

Agg 0.4%

↓ -0.2%

P 0.4%

K 0.3%

SAS

Stephen A. Smith

Vol $55.0K Spread 0.1%

Agg 0.4%

↓ -0.3%

K 0.5%

P 0.4%

Chris Murphy

Vol $660 Spread 0.3%

Agg 0.4%

↓ -0.3%

K 0.7%

P 0.4%

George Clooney

Vol $2.2K Spread —

Agg 0.4%

↓ -0.2%

P 0.4%

Polymarket 0.4%

Vol $2.2K 0.3–0.4¢

Jamie Dimon

Vol $0 Spread —

Agg 0.4%

↓ -0.2%

K 0.4%

Kalshi 0.4%

Vol $0 0.3–0.4¢

Jasmine Crockett

Vol $68 Spread —

Agg 0.4%

↓ -0.2%

P 0.4%

Polymarket 0.4%

Vol $68 0.3–0.4¢

Oprah Winfrey

Vol $1.2K Spread —

Agg 0.4%

↓ -0.1%

P 0.4%

Polymarket 0.4%

Vol $1.2K 0.3–0.4¢

Ruben Gallego

Vol $2.9K Spread 0.2%

Agg 0.4%

↓ -0.8%

K 0.5%

P 0.4%

John Fetterman

Vol $430 Spread 0.2%

Agg 0.3%

↓ -0.9%

P 0.4%

K 0.2%

Zohran Mamdani

Vol $23.1K Spread 0.1%

Agg 0.3%

↓ -0.3%

NYC Mayor

P 0.4%

K 0.3%

Andrew Yang

Vol $244 Spread —

Agg 0.3%

↓ -0.3%

P 0.3%

Polymarket 0.3%

Vol $244 0.2–0.3¢

Barack Obama

Vol $1.1K Spread 0.0%

Agg 0.3%

↓ -0.4%

K 0.3%

P 0.3%

BOR

Beto O’Rourke

Vol $291 Spread —

Agg 0.3%

↓ -0.6%

P 0.3%

Polymarket 0.3%

Vol $291 0.2–0.3¢

Gina Raimondo

Vol $628 Spread 0.1%

Agg 0.3%

↓ -0.2%

P 0.3%

K 0.2%

Jared Polis

Vol $77 Spread 0.1%

Agg 0.3%

↓ -0.7%

P 0.3%

K 0.2%

Lebron James

Vol $697 Spread 0.2%

Agg 0.3%

↓ -0.6%

P 0.3%

K 0.1%

Liz Cheney

Vol $2.8K Spread 0.2%

Agg 0.3%

↓ -0.3%

P 0.3%

K 0.1%

MrBeast

Vol $204.1K Spread —

Agg 0.3%

↓ -0.3%

P 0.3%

Polymarket 0.3%

Vol $204.1K 0.2–0.3¢

Hilary Clinton

Vol $391 Spread 0.1%

Agg 0.2%

↓ -0.3%

P 0.3%

K 0.2%

Kim Kardashian

Vol $252.8K Spread —

Agg 0.2%

↓ -0.5%

P 0.2%

Polymarket 0.2%

Vol $252.8K 0.1–0.2¢

Phil Murphy

Vol $4.9K Spread 0.1%

Agg 0.2%

↓ -0.4%

P 0.2%

K 0.1%

Tim Walz

Vol $2.2K Spread 0.0%

Agg 0.2%

↓ -0.4%

K 0.2%

P 0.2%

Outcome	Aggregated	Spread	Volume	Kalshi	Polymarket	ForecastEx
GN Gavin Newsom California Governor	17.5% ↓ -17.8%	9.5%	$13.5K	Kalshi 17.5% 17–18¢ Vol $6.1K	Polymarket 17.5% 17.5–17.6¢ Vol $7.4K	ForecastEx 27.0% 27¢ Vol $0
JO Jon Ossoff	15.6% ↑ +12.1%	1.5%	$18.7K	Kalshi 14.5% 14–15¢ Vol $4.7K	Polymarket 16.0% 15.9–16¢ Vol $14.1K	ForecastEx — —
AOC Alexandria Ocasio-Cortez NY Representative	15.0% ↑ +3.1%	3.4%	$35.2K	Kalshi 14.5% 14–15¢ Vol $14.5K	Polymarket 15.4% 15.3–15.4¢ Vol $20.8K	ForecastEx 12.0% 12¢ Vol $0
KH Kamala Harris	7.8% ↑ +3.9%	1.9%	$11.4K	Kalshi 9.5% 9.4–9.5¢ Vol $1.3K	Polymarket 7.6% 7.5–7.7¢ Vol $10.1K	ForecastEx 9.0% 9¢ Vol $0
MK Mark Kelly	5.7% ↑ +3.9%	3.1%	$10.2K	Kalshi 6.2% 6.1–6.2¢ Vol $8.9K	Polymarket 3.1% 3–3.1¢ Vol $1.3K	ForecastEx — —
PB Pete Buttigieg	5.3% ↑ +0.8%	8.8%	$2.3K	Kalshi 5.5% 5.4–5.5¢ Vol $411	Polymarket 5.3% 5.2–5.3¢ Vol $1.8K	ForecastEx 14.0% 14¢ Vol $0
JS Josh Shapiro	4.9% ↑ +0.7%	5.5%	$1.3K	Kalshi 4.6% 4.5–4.6¢ Vol $94	Polymarket 5.0% 4.9–5¢ Vol $1.2K	ForecastEx 10.0% 10¢ Vol $0
RE Rahm Emanuel	4.5% ↑ +2.5%	2.2%	$12.0K	Kalshi 4.5% 4.4–4.6¢ Vol $11.8K	Polymarket 2.4% 2.3–2.4¢ Vol $208	ForecastEx — —
AB Andy Beshear	3.4% ↑ +0.8%	6.7%	$545	Kalshi 3.6% 3.5–3.6¢ Vol $479	Polymarket 2.4% 2.3–2.4¢ Vol $66	ForecastEx 9.0% 9¢ Vol $0
WM Wes Moore	2.4% — +0.0%	3.6%	$21.3K	Kalshi 2.5% 2.4–2.5¢ Vol $21.0K	Polymarket 1.5% 1.4–1.5¢ Vol $226	ForecastEx 5.0% 5¢ Vol $0
RK Ro Khanna	2.2% ↑ +1.0%	0.1%	$10.1K	Kalshi 2.3% 2.2–2.3¢ Vol $171	Polymarket 2.2% 2.1–2.3¢ Vol $9.9K	ForecastEx — —
JT James Talarico	1.7% ↑ +1.2%	—	$3.3K	Kalshi 1.7% 1.6–1.7¢ Vol $3.3K	Polymarket — —	ForecastEx — —
JS Jon Stewart Comedian	1.4% ↑ +0.5%	0.9%	$1.8K	Kalshi 1.1% 1–1.2¢ Vol $1.3K	Polymarket 2.0% 1.9–2¢ Vol $542	ForecastEx — —
MO Michelle Obama	1.2% ↑ +0.2%	0.2%	$289	Kalshi 1.2% 1.1–1.2¢ Vol $289	Polymarket 1.0% 0.9–1¢ Vol $0	ForecastEx — —
GW Gretchen Whitmer	1.1% ↓ -0.7%	7.1%	$2.9K	Kalshi 1.0% 0.9–1¢ Vol $2	Polymarket 1.2% 1.1–1.2¢ Vol $2.9K	ForecastEx 8.0% 8¢ Vol $0
JBP J.B. Pritzker	1.1% ↓ -1.0%	2.9%	$1.6K	Kalshi 2.6% 2.5–2.6¢ Vol $16	Polymarket 1.1% 1–1.1¢ Vol $1.6K	ForecastEx 4.0% 4¢ Vol $0
DJ Dwayne Johnson	1.1% ↓ -0.2%	0.9%	$2.7K	Kalshi 0.2% 0.1–0.2¢ Vol $0	Polymarket 1.1% 1–1.1¢ Vol $2.7K	ForecastEx — —
RW Raphael Warnock	0.7% ↑ +0.2%	0.0%	$291	Kalshi 0.8% 0.7–0.8¢ Vol $14	Polymarket 0.7% 0.6–0.8¢ Vol $277	ForecastEx — —
CB Cory Booker	0.6% ↓ -0.1%	0.1%	$4.8K	Kalshi 0.6% 0.5–0.7¢ Vol $1.2K	Polymarket 0.5% 0.5–0.6¢ Vol $3.6K	ForecastEx — —
MC Mark Cuban	0.6% ↓ -0.2%	0.4%	$3.9K	Kalshi 0.9% 0.8–1¢ Vol $19	Polymarket 0.5% 0.5–0.6¢ Vol $3.8K	ForecastEx — —
BS Bernie Sanders	0.6% ↑ +0.1%	0.1%	$712	Kalshi 0.7% 0.6–0.7¢ Vol $1	Polymarket 0.5% 0.5–0.6¢ Vol $711	ForecastEx — —
CC Chelsea Clinton	0.5% — +0.0%	—	$468	Kalshi — —	Polymarket 0.5% 0.5–0.6¢ Vol $468	ForecastEx — —
ES Elissa Slotkin	0.5% — +0.0%	—	$1	Kalshi 0.5% 0.5–0.6¢ Vol $1	Polymarket — —	ForecastEx — —
HB Hunter Biden	0.5% — +0.0%	0.0%	$1.4K	Kalshi 0.5% 0.5–0.6¢ Vol $432	Polymarket 0.5% 0.5–0.6¢ Vol $925	ForecastEx — —
RC Roy Cooper	0.4% ↓ -0.2%	0.2%	$37	Kalshi 0.3% 0.2–0.3¢ Vol $0	Polymarket 0.4% 0.4–0.5¢ Vol $37	ForecastEx — —
SAS Stephen A. Smith	0.4% ↓ -0.3%	0.1%	$55.0K	Kalshi 0.5% 0.5–0.6¢ Vol $9	Polymarket 0.4% 0.4–0.5¢ Vol $55.0K	ForecastEx — —
CM Chris Murphy	0.4% ↓ -0.3%	0.3%	$660	Kalshi 0.7% 0.6–0.7¢ Vol $92	Polymarket 0.4% 0.3–0.4¢ Vol $569	ForecastEx — —
GC George Clooney	0.4% ↓ -0.2%	—	$2.2K	Kalshi — —	Polymarket 0.4% 0.3–0.4¢ Vol $2.2K	ForecastEx — —
JD Jamie Dimon	0.4% ↓ -0.2%	—	$0	Kalshi 0.4% 0.3–0.4¢ Vol $0	Polymarket — —	ForecastEx — —
JC Jasmine Crockett	0.4% ↓ -0.2%	—	$68	Kalshi — —	Polymarket 0.4% 0.3–0.4¢ Vol $68	ForecastEx — —
OW Oprah Winfrey	0.4% ↓ -0.1%	—	$1.2K	Kalshi — —	Polymarket 0.4% 0.3–0.4¢ Vol $1.2K	ForecastEx — —
RG Ruben Gallego	0.4% ↓ -0.8%	0.2%	$2.9K	Kalshi 0.5% 0.5–0.6¢ Vol $0	Polymarket 0.4% 0.3–0.4¢ Vol $2.9K	ForecastEx — —
JF John Fetterman	0.3% ↓ -0.9%	0.2%	$430	Kalshi 0.2% 0.1–0.2¢ Vol $4	Polymarket 0.4% 0.3–0.4¢ Vol $427	ForecastEx — —
ZM Zohran Mamdani NYC Mayor	0.3% ↓ -0.3%	0.1%	$23.1K	Kalshi 0.3% 0.2–0.3¢ Vol $21.6K	Polymarket 0.4% 0.3–0.4¢ Vol $1.5K	ForecastEx — —
AY Andrew Yang	0.3% ↓ -0.3%	—	$244	Kalshi — —	Polymarket 0.3% 0.2–0.3¢ Vol $244	ForecastEx — —
BO Barack Obama	0.3% ↓ -0.4%	0.0%	$1.1K	Kalshi 0.3% 0.2–0.3¢ Vol $1	Polymarket 0.3% 0.2–0.3¢ Vol $1.1K	ForecastEx — —
BOR Beto O’Rourke	0.3% ↓ -0.6%	—	$291	Kalshi — —	Polymarket 0.3% 0.2–0.3¢ Vol $291	ForecastEx — —
GR Gina Raimondo	0.3% ↓ -0.2%	0.1%	$628	Kalshi 0.2% 0.1–0.2¢ Vol $0	Polymarket 0.3% 0.2–0.3¢ Vol $628	ForecastEx — —
JP Jared Polis	0.3% ↓ -0.7%	0.1%	$77	Kalshi 0.2% 0.1–0.2¢ Vol $0	Polymarket 0.3% 0.2–0.3¢ Vol $77	ForecastEx — —
LJ Lebron James	0.3% ↓ -0.6%	0.2%	$697	Kalshi 0.1% 0–0.1¢ Vol $0	Polymarket 0.3% 0.2–0.3¢ Vol $697	ForecastEx — —
LC Liz Cheney	0.3% ↓ -0.3%	0.2%	$2.8K	Kalshi 0.1% 0–0.1¢ Vol $0	Polymarket 0.3% 0.2–0.3¢ Vol $2.8K	ForecastEx — —
MR MrBeast	0.3% ↓ -0.3%	—	$204.1K	Kalshi — —	Polymarket 0.3% 0.2–0.3¢ Vol $204.1K	ForecastEx — —
HC Hilary Clinton	0.2% ↓ -0.3%	0.1%	$391	Kalshi 0.2% 0.1–0.2¢ Vol $1	Polymarket 0.3% 0.2–0.3¢ Vol $390	ForecastEx — —
KK Kim Kardashian	0.2% ↓ -0.5%	—	$252.8K	Kalshi — —	Polymarket 0.2% 0.1–0.2¢ Vol $252.8K	ForecastEx — —
PM Phil Murphy	0.2% ↓ -0.4%	0.1%	$4.9K	Kalshi 0.1% 0–0.1¢ Vol $0	Polymarket 0.2% 0.1–0.2¢ Vol $4.9K	ForecastEx — —
TW Tim Walz	0.2% ↓ -0.4%	0.0%	$2.2K	Kalshi 0.2% 0.1–0.2¢ Vol $0	Polymarket 0.2% 0.1–0.2¢ Vol $2.2K	ForecastEx — —

Arbitrage Scanner

Current cross-venue opportunities with fee calculations

Minimum Spread 1.5%

Include fees

Show only actionable

Pairs (Venue-to-Venue)

Outcome	Venue Pair	Leg A (Buy)	Leg B (Sell)	Gross Spread	After Fees	Actionable	Trade Now
MK Mark Kelly	Polymarket → Kalshi	Buy @ P 3.1¢	Sell @ K 6.1¢	+3.00%	+2.93%	Yes	P ↗︎ K ↗︎
RE Rahm Emanuel	Polymarket → Kalshi	Buy @ P 2.4¢	Sell @ K 4.4¢	+2.00%	+1.93%	Yes	P ↗︎ K ↗︎
KH Kamala Harris	Polymarket → Kalshi	Buy @ P 7.7¢	Sell @ K 9.4¢	+1.70%	+1.61%	Yes	P ↗︎ K ↗︎
JBP J.B. Pritzker	Polymarket → Kalshi	Buy @ P 1.1¢	Sell @ K 2.5¢	+1.40%	+1.33%	No	P ↗︎ K ↗︎
AB Andy Beshear	Polymarket → Kalshi	Buy @ P 2.4¢	Sell @ K 3.5¢	+1.10%	+1.03%	No	P ↗︎ K ↗︎
WM Wes Moore	Polymarket → Kalshi	Buy @ P 1.5¢	Sell @ K 2.4¢	+0.90%	+0.83%	No	P ↗︎ K ↗︎
JO Jon Ossoff	Kalshi → Polymarket	Buy @ K 15¢	Sell @ P 15.9¢	+0.90%	+0.75%	No	K ↗︎ P ↗︎
DJ Dwayne Johnson	Kalshi → Polymarket	Buy @ K 0.2¢	Sell @ P 1¢	+0.80%	+0.73%	No	K ↗︎ P ↗︎
JS Jon Stewart Comedian	Kalshi → Polymarket	Buy @ K 1.2¢	Sell @ P 1.9¢	+0.70%	+0.63%	No	K ↗︎ P ↗︎
JS Josh Shapiro	Kalshi → Polymarket	Buy @ K 4.6¢	Sell @ P 4.9¢	+0.30%	+0.23%	No	K ↗︎ P ↗︎
AOC Alexandria Ocasio-Cortez NY Representative	Kalshi → Polymarket	Buy @ K 15¢	Sell @ P 15.3¢	+0.30%	+0.15%	No	K ↗︎ P ↗︎
MC Mark Cuban	Polymarket → Kalshi	Buy @ P 0.6¢	Sell @ K 0.8¢	+0.20%	+0.13%	No	P ↗︎ K ↗︎
CM Chris Murphy	Polymarket → Kalshi	Buy @ P 0.4¢	Sell @ K 0.6¢	+0.20%	+0.13%	No	P ↗︎ K ↗︎
PB Pete Buttigieg	Polymarket → Kalshi	Buy @ P 5.3¢	Sell @ K 5.4¢	+0.10%	+0.03%	No	P ↗︎ K ↗︎
RC Roy Cooper	Kalshi → Polymarket	Buy @ K 0.3¢	Sell @ P 0.4¢	+0.10%	+0.03%	No	K ↗︎ P ↗︎
RG Ruben Gallego	Polymarket → Kalshi	Buy @ P 0.4¢	Sell @ K 0.5¢	+0.10%	+0.03%	No	P ↗︎ K ↗︎
JF John Fetterman	Kalshi → Polymarket	Buy @ K 0.2¢	Sell @ P 0.3¢	+0.10%	+0.03%	No	K ↗︎ P ↗︎
LJ Lebron James	Kalshi → Polymarket	Buy @ K 0.1¢	Sell @ P 0.2¢	+0.10%	+0.03%	No	K ↗︎ P ↗︎
LC Liz Cheney	Kalshi → Polymarket	Buy @ K 0.1¢	Sell @ P 0.2¢	+0.10%	+0.03%	No	K ↗︎ P ↗︎
MO Michelle Obama	Polymarket → Kalshi	Buy @ P 1¢	Sell @ K 1.1¢	+0.10%	+0.03%	No	P ↗︎ K ↗︎
GW Gretchen Whitmer	Kalshi → Polymarket	Buy @ K 1¢	Sell @ P 1.1¢	+0.10%	+0.03%	No	K ↗︎ P ↗︎
BS Bernie Sanders	Polymarket → Kalshi	Buy @ P 0.6¢	Sell @ K 0.6¢	+0.00%	-0.07%	No	P ↗︎ K ↗︎
SAS Stephen A. Smith	Polymarket → Kalshi	Buy @ P 0.5¢	Sell @ K 0.5¢	+0.00%	-0.07%	No	P ↗︎ K ↗︎
ZM Zohran Mamdani NYC Mayor	Kalshi → Polymarket	Buy @ K 0.3¢	Sell @ P 0.3¢	+0.00%	-0.07%	No	K ↗︎ P ↗︎
GR Gina Raimondo	Kalshi → Polymarket	Buy @ K 0.2¢	Sell @ P 0.2¢	+0.00%	-0.07%	No	K ↗︎ P ↗︎
JP Jared Polis	Kalshi → Polymarket	Buy @ K 0.2¢	Sell @ P 0.2¢	+0.00%	-0.07%	No	K ↗︎ P ↗︎
HC Hilary Clinton	Kalshi → Polymarket	Buy @ K 0.2¢	Sell @ P 0.2¢	+0.00%	-0.07%	No	K ↗︎ P ↗︎
PM Phil Murphy	Kalshi → Polymarket	Buy @ K 0.1¢	Sell @ P 0.1¢	+0.00%	-0.07%	No	K ↗︎ P ↗︎
RW Raphael Warnock	Polymarket → Kalshi	Buy @ P 0.8¢	Sell @ K 0.7¢	-0.10%	-0.17%	No	P ↗︎ K ↗︎
CB Cory Booker	Polymarket → Kalshi	Buy @ P 0.6¢	Sell @ K 0.5¢	-0.10%	-0.17%	No	P ↗︎ K ↗︎
HB Hunter Biden	Kalshi → Polymarket	Buy @ K 0.6¢	Sell @ P 0.5¢	-0.10%	-0.17%	No	K ↗︎ P ↗︎
BO Barack Obama	Kalshi → Polymarket	Buy @ K 0.3¢	Sell @ P 0.2¢	-0.10%	-0.17%	No	K ↗︎ P ↗︎
TW Tim Walz	Kalshi → Polymarket	Buy @ K 0.2¢	Sell @ P 0.1¢	-0.10%	-0.17%	No	K ↗︎ P ↗︎
RK Ro Khanna	Polymarket → Kalshi	Buy @ P 2.3¢	Sell @ K 2.2¢	-0.10%	-0.17%	No	P ↗︎ K ↗︎
GN Gavin Newsom California Governor	Kalshi → Polymarket	Buy @ K 18¢	Sell @ P 17.5¢	-0.50%	-0.68%	No	K ↗︎ P ↗︎

Outcome Diff

Outcome A	Outcome B	Venue	A Odds	B Odds	Diff	Strategy	Trade Now
GN Gavin Newsom	RK Ro Khanna	Polymarket	A 17.5%	B 2.2%	+15.35%	Buy spread	P ↗︎
GN Gavin Newsom	RE Rahm Emanuel	Polymarket	A 17.5%	B 2.4%	+15.20%	Buy spread	P ↗︎
GN Gavin Newsom	AB Andy Beshear	Polymarket	A 17.5%	B 2.4%	+15.20%	Buy spread	P ↗︎
GN Gavin Newsom	JBP J.B. Pritzker	Kalshi	A 17.5%	B 2.6%	+14.95%	Buy spread	K ↗︎
GN Gavin Newsom	MK Mark Kelly	Polymarket	A 17.5%	B 3.1%	+14.50%	Buy spread	P ↗︎
GN Gavin Newsom	AB Andy Beshear	Kalshi	A 17.5%	B 3.6%	+13.95%	Buy spread	K ↗︎
JO Jon Ossoff	RK Ro Khanna	Polymarket	A 16.0%	B 2.2%	+13.75%	Buy spread	P ↗︎
JO Jon Ossoff	RE Rahm Emanuel	Polymarket	A 16.0%	B 2.4%	+13.60%	Buy spread	P ↗︎
JO Jon Ossoff	AB Andy Beshear	Polymarket	A 16.0%	B 2.4%	+13.60%	Buy spread	P ↗︎
AOC Alexandria Ocasio-Cortez	RK Ro Khanna	Polymarket	A 15.4%	B 2.2%	+13.15%	Buy spread	P ↗︎
GN Gavin Newsom	RE Rahm Emanuel	Kalshi	A 17.5%	B 4.5%	+13.00%	Buy spread	K ↗︎
AOC Alexandria Ocasio-Cortez	RE Rahm Emanuel	Polymarket	A 15.4%	B 2.4%	+13.00%	Buy spread	P ↗︎
AOC Alexandria Ocasio-Cortez	AB Andy Beshear	Polymarket	A 15.4%	B 2.4%	+13.00%	Buy spread	P ↗︎
GN Gavin Newsom	JS Josh Shapiro	Kalshi	A 17.5%	B 4.6%	+12.95%	Buy spread	K ↗︎
JO Jon Ossoff	MK Mark Kelly	Polymarket	A 16.0%	B 3.1%	+12.90%	Buy spread	P ↗︎
GN Gavin Newsom	JS Josh Shapiro	Polymarket	A 17.5%	B 5.0%	+12.60%	Buy spread	P ↗︎
GN Gavin Newsom	PB Pete Buttigieg	Polymarket	A 17.5%	B 5.3%	+12.30%	Buy spread	P ↗︎
AOC Alexandria Ocasio-Cortez	MK Mark Kelly	Polymarket	A 15.4%	B 3.1%	+12.30%	Buy spread	P ↗︎
GN Gavin Newsom	PB Pete Buttigieg	Kalshi	A 17.5%	B 5.5%	+12.05%	Buy spread	K ↗︎
JO Jon Ossoff	JBP J.B. Pritzker	Kalshi	A 14.5%	B 2.6%	+11.95%	Buy spread	K ↗︎
AOC Alexandria Ocasio-Cortez	JBP J.B. Pritzker	Kalshi	A 14.5%	B 2.6%	+11.95%	Buy spread	K ↗︎
GN Gavin Newsom	MK Mark Kelly	Kalshi	A 17.5%	B 6.2%	+11.35%	Buy spread	K ↗︎
JO Jon Ossoff	JS Josh Shapiro	Polymarket	A 16.0%	B 5.0%	+11.00%	Buy spread	P ↗︎
JO Jon Ossoff	AB Andy Beshear	Kalshi	A 14.5%	B 3.6%	+10.95%	Buy spread	K ↗︎
AOC Alexandria Ocasio-Cortez	AB Andy Beshear	Kalshi	A 14.5%	B 3.6%	+10.95%	Buy spread	K ↗︎
JO Jon Ossoff	PB Pete Buttigieg	Polymarket	A 16.0%	B 5.3%	+10.70%	Buy spread	P ↗︎
AOC Alexandria Ocasio-Cortez	JS Josh Shapiro	Polymarket	A 15.4%	B 5.0%	+10.40%	Buy spread	P ↗︎
AOC Alexandria Ocasio-Cortez	PB Pete Buttigieg	Polymarket	A 15.4%	B 5.3%	+10.10%	Buy spread	P ↗︎
JO Jon Ossoff	RE Rahm Emanuel	Kalshi	A 14.5%	B 4.5%	+10.00%	Buy spread	K ↗︎
AOC Alexandria Ocasio-Cortez	RE Rahm Emanuel	Kalshi	A 14.5%	B 4.5%	+10.00%	Buy spread	K ↗︎

Kalshi Trading Fee 1% (min $0.07, max $1.75) per side

Polymarket Trading Fee 0% (gas only)

Gemini Trading Fee 0.40% per side

Polymarket US Trading Fee 0% (gas only)

After-fee spreads apply the configured taker-fee model per side. Depth/slippage is not modeled in this scanner.

Methodology & Data Mapping

How we aggregate, normalize, and map cross-platform data

Aggregation Method

Default: Volume-Weighted Average Price (VWAP)

Weights each mapped market by its reported 24H USD volume at snapshot time. If volume is unavailable, we fall back to a simple average for that snapshot.

Use the VWAP/Simple toggle above the chart to switch aggregation views.

Data Sources & Cadence

Kalshi: Official API (best bid/ask + last + 24H volume/liquidity when available).

Polymarket: Market data via their API (token prices + best bid/ask + 24H volume/liquidity when available).

ForecastEx: FEX API (price from latest_prices; 24H USD volume estimated from trades as sum(quantity * yes_price); no bid/ask).

Event data is updated hourly. Older history is downsampled.

Outcome Mapping

Each event links one or more markets per provider. We normalize labels, map provider outcomes into a shared outcome list, and merge mapped markets where appropriate.

Spread & Liquidity

Cross-venue spread: Max–min difference across available venue probabilities for the same outcome.

Liquidity: Relative per-venue indicators based on provider liquidity fields (no depth/slippage modeling).

Arbitrage: Computed from best bid/ask when available (otherwise mid); after-fee spread applies the configured fee model only.

Prediction Markets 2028 Democratic Presidential Nominee

2028 Democratic Presidential Nominee Odds

Probability Over Time

Current Odds Snapshot

Arbitrage Scanner

Pairs (Venue-to-Venue)

Outcome Diff

Methodology & Data Mapping