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US Presidential 2028 Odds at Prediction Markets

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Updated 9 minutes ago · 6:40 PM PDT

Prediction markets expect JD Vance to win the 2028 Presidential Election, with his victory sitting at 77.0% probability (-335). A J.D. Vance win stands at 19.7% (+407), while deeper field candidates remain unlikely at sub-10% probability. Our 2028 US election tracker aggregates live odds from 4 prediction markets. The total volume in the last 24 hours stands at $4.3M, with $41.7K at Kalshi and $4.3M at Polymarket. Aggregated cross-platform odds for US Election updated hourly with current probability synthesis and arbitrage detection.

Largest Spread

2.02%

J.D. Vance → View arbs

Consensus Leader

77.0%

Robert F. Kennedy Jr. +69.0%

24H Volume (Share)

$4.3M

Momentum Leader

+69.0%

Robert F. Kennedy Jr. YTD change

Period:

Platform:

Probability Over Time

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Aggregated (VWAP)

Volume

Kalshi

Polymarket

Gemini

Cross-Venue Spread

Current Odds Snapshot

Current probabilities across platforms with liquidity indicators

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RFK

Robert F. Kennedy Jr.

Vol $0 Spread —

Agg 77.0%

↑ +69.0%

O 77.0%

OG 77.0%

77¢

JDV

J.D. Vance

Vol $57.8K Spread 4.5%

Agg 19.7%

↓ -10.6%

O 22.0%

G 20.5%

P 20.3%

K 17.5%

OG 22.0%

22¢

Gemini 20.5%

Vol $0 14–27¢

Polymarket 20.3%

Vol $47.1K 20.2–20.3¢

Kalshi 17.5%

Vol $10.7K 17–18¢

Gavin Newsom

Vol $78.3K Spread 1.8%

Agg 17.2%

↓ -1.4%

O 19.0%

K 17.5%

P 17.2%

OG 19.0%

19¢

Kalshi 17.5%

Vol $10.4K 17–18¢

Polymarket 17.2%

Vol $68.0K 17.1–17.2¢

Marco Rubio

Vol $49.4K Spread 1.8%

Agg 16.7%

↑ +12.1%

O 18.0%

K 17.5%

G 16.5%

P 16.2%

OG 18.0%

18¢

Kalshi 17.5%

Vol $17.3K 17–18¢

Gemini 16.5%

Vol $31 10–23¢

Polymarket 16.2%

Vol $32.1K 16.1–16.3¢

Cory Booker

Vol $0 Spread —

Agg 8.0%

— +0.0%

O 8.0%

OG 8.0%

8¢

Ted Cruz

Vol $0 Spread —

Agg 8.0%

— +0.0%

O 8.0%

OG 8.0%

8¢

AOC

Alexandria Ocasio-Cortez

Vol $86.8K Spread 1.0%

Agg 5.0%

↓ -2.5%

O 6.0%

K 5.5%

P 5.0%

OG 6.0%

6¢

Kalshi 5.5%

Vol $516 5–6¢

Polymarket 5.0%

Vol $86.3K 4.9–5¢

Kamala Harris

Vol $83.8K Spread 1.8%

Agg 3.3%

↑ +0.2%

O 5.0%

K 3.5%

P 3.3%

OG 5.0%

5¢

Kalshi 3.5%

Vol $295 3–4¢

Polymarket 3.3%

Vol $83.5K 3.2–3.3¢

Josh Shapiro

Vol $47.7K Spread 2.6%

Agg 2.5%

↑ +0.1%

O 5.0%

K 4.5%

P 2.5%

OG 5.0%

5¢

Kalshi 4.5%

Vol $1.4K 4–5¢

Polymarket 2.5%

Vol $46.3K 2.4–2.5¢

DJT

Donald J. Trump

Vol $71.7K Spread 1.7%

Agg 2.3%

↓ -0.9%

G 4.0%

K 2.5%

P 2.3%

Gemini 4.0%

Vol $0 0–8¢

Kalshi 2.5%

Vol $223 2–3¢

Polymarket 2.3%

Vol $71.5K 2.2–2.4¢

Pete Buttigieg

Vol $13.7K Spread 2.2%

Agg 1.9%

↓ -0.7%

O 4.0%

K 2.5%

P 1.8%

OG 4.0%

4¢

Kalshi 2.5%

Vol $102 2–3¢

Polymarket 1.8%

Vol $13.6K 1.8–1.9¢

DTR

Dwayne 'The Rock' Johnson

Vol $100.2K Spread —

Agg 1.7%

↓ -0.4%

P 1.7%

Polymarket 1.7%

Vol $100.2K 1.6–1.8¢

Ron DeSantis

Vol $22.1K Spread 2.4%

Agg 1.7%

↑ +0.2%

O 4.0%

K 2.5%

P 1.7%

OG 4.0%

4¢

Kalshi 2.5%

Vol $1 2–3¢

Polymarket 1.7%

Vol $22.1K 1.6–1.7¢

Tucker Carlson

Vol $30.5K Spread —

Agg 1.7%

↑ +0.1%

P 1.7%

Polymarket 1.7%

Vol $30.5K 1.6–1.7¢

Andy Beshear

Vol $103.3K Spread 1.5%

Agg 1.5%

↓ -0.3%

O 3.0%

P 1.6%

K 1.5%

OG 3.0%

3¢

Polymarket 1.6%

Vol $103.0K 1.5–1.6¢

Kalshi 1.5%

Vol $246 1–2¢

JBP

J.B. Pritzker

Vol $2.1K Spread 2.7%

Agg 1.4%

— +0.0%

O 4.0%

K 2.5%

P 1.4%

OG 4.0%

4¢

Kalshi 2.5%

Vol $170 2–3¢

Polymarket 1.4%

Vol $1.9K 1.3–1.4¢

Ivanka Trump

Vol $25.8K Spread —

Agg 1.3%

— +0.0%

P 1.3%

Polymarket 1.3%

Vol $25.8K 1.2–1.3¢

Michelle Obama

Vol $13.9K Spread —

Agg 1.3%

↑ +0.5%

P 1.3%

Polymarket 1.3%

Vol $13.9K 1.2–1.3¢

Nikki Haley

Vol $294.3K Spread 3.5%

Agg 1.3%

↑ +0.5%

O 4.0%

P 1.3%

K 0.5%

OG 4.0%

4¢

Polymarket 1.3%

Vol $294.3K 1.2–1.3¢

Kalshi 0.5%

Vol $1 0–1¢

Elon Musk

Vol $852.0K Spread —

Agg 1.2%

↑ +0.1%

P 1.2%

Polymarket 1.2%

Vol $852.0K 1.1–1.2¢

Jamie Dimon

Vol $18.5K Spread 0.7%

Agg 1.1%

↑ +0.4%

P 1.2%

K 0.5%

Polymarket 1.2%

Vol $18.5K 1.1–1.2¢

Kalshi 0.5%

Vol $4 0–1¢

Gretchen Whitmer

Vol $64.2K Spread 2.9%

Agg 1.1%

↓ -1.3%

O 4.0%

K 1.5%

P 1.1%

OG 4.0%

4¢

Kalshi 1.5%

Vol $80 1–2¢

Polymarket 1.1%

Vol $64.1K 1–1.1¢

Tulsi Gabbard

Vol $418.8K Spread 3.5%

Agg 1.0%

↑ +0.3%

O 4.0%

P 1.1%

K 0.5%

OG 4.0%

4¢

Polymarket 1.1%

Vol $418.6K 1–1.1¢

Kalshi 0.5%

Vol $149 0–1¢

SAS

Stephen A. Smith

Vol $101.6K Spread 0.5%

Agg 1.0%

↑ +0.1%

K 1.5%

P 1.0%

Kalshi 1.5%

Vol $51 1–2¢

Polymarket 1.0%

Vol $101.6K 0.9–1¢

Greg Abbott

Vol $43.9K Spread 0.4%

Agg 1.0%

↑ +0.2%

P 1.0%

K 0.5%

Polymarket 1.0%

Vol $43.9K 0.9–1¢

Kalshi 0.5%

Vol $0 0–1¢

Wes Moore

Vol $294.9K Spread 0.5%

Agg 1.0%

↓ -0.6%

K 1.5%

P 1.0%

Kalshi 1.5%

Vol $7 1–2¢

Polymarket 1.0%

Vol $294.9K 0.9–1¢

Glenn Youngkin

Vol $214.2K Spread 2.2%

Agg 0.9%

↑ +0.1%

O 3.0%

K 1.5%

P 0.9%

OG 3.0%

3¢

Kalshi 1.5%

Vol $29 1–2¢

Polymarket 0.9%

Vol $214.2K 0.8–0.9¢

DJT

Donald J. Trump Jr.

Vol $42.9K Spread 0.6%

Agg 0.9%

↓ -0.4%

K 1.5%

P 0.9%

Kalshi 1.5%

Vol $2 1–2¢

Polymarket 0.9%

Vol $42.9K 0.8–0.9¢

Tim Walz

Vol $146.1K Spread 2.5%

Agg 0.9%

↑ +0.1%

O 3.0%

P 0.9%

K 0.5%

OG 3.0%

3¢

Polymarket 0.9%

Vol $146.1K 0.8–0.9¢

Kalshi 0.5%

Vol $0 0–1¢

Vivek Ramaswamy

Vol $518.1K Spread 2.5%

Agg 0.9%

↓ -0.1%

O 3.0%

P 0.9%

K 0.5%

OG 3.0%

3¢

Polymarket 0.9%

Vol $518.1K 0.8–0.9¢

Kalshi 0.5%

Vol $24 0–1¢

Zohran Mamdani

Vol $112.1K Spread —

Agg 0.9%

— +0.0%

P 0.9%

Polymarket 0.9%

Vol $112.1K 0.8–0.9¢

Kim Kardashian

Vol $197.5K Spread —

Agg 0.8%

↓ -0.1%

P 0.8%

Polymarket 0.8%

Vol $197.5K 0.7–0.8¢

LeBron James

Vol $198.8K Spread —

Agg 0.8%

↓ -0.1%

P 0.8%

Polymarket 0.8%

Vol $198.8K 0.7–0.8¢

Outcome	Aggregated	Spread	Volume	Kalshi	Polymarket	Gemini	OG
RFK Robert F. Kennedy Jr.	77.0% ↑ +69.0%	—	$0	Kalshi — —	Polymarket — —	Gemini — —	OG 77.0% 77¢
JDV J.D. Vance	19.7% ↓ -10.6%	4.5%	$57.8K	Kalshi 17.5% 17–18¢ Vol $10.7K	Polymarket 20.3% 20.2–20.3¢ Vol $47.1K	Gemini 20.5% 14–27¢ Vol $0	OG 22.0% 22¢
GN Gavin Newsom	17.2% ↓ -1.4%	1.8%	$78.3K	Kalshi 17.5% 17–18¢ Vol $10.4K	Polymarket 17.2% 17.1–17.2¢ Vol $68.0K	Gemini — —	OG 19.0% 19¢
MR Marco Rubio	16.7% ↑ +12.1%	1.8%	$49.4K	Kalshi 17.5% 17–18¢ Vol $17.3K	Polymarket 16.2% 16.1–16.3¢ Vol $32.1K	Gemini 16.5% 10–23¢ Vol $31	OG 18.0% 18¢
CB Cory Booker	8.0% — +0.0%	—	$0	Kalshi — —	Polymarket — —	Gemini — —	OG 8.0% 8¢
TC Ted Cruz	8.0% — +0.0%	—	$0	Kalshi — —	Polymarket — —	Gemini — —	OG 8.0% 8¢
AOC Alexandria Ocasio-Cortez	5.0% ↓ -2.5%	1.0%	$86.8K	Kalshi 5.5% 5–6¢ Vol $516	Polymarket 5.0% 4.9–5¢ Vol $86.3K	Gemini — —	OG 6.0% 6¢
KH Kamala Harris	3.3% ↑ +0.2%	1.8%	$83.8K	Kalshi 3.5% 3–4¢ Vol $295	Polymarket 3.3% 3.2–3.3¢ Vol $83.5K	Gemini — —	OG 5.0% 5¢
JS Josh Shapiro	2.5% ↑ +0.1%	2.6%	$47.7K	Kalshi 4.5% 4–5¢ Vol $1.4K	Polymarket 2.5% 2.4–2.5¢ Vol $46.3K	Gemini — —	OG 5.0% 5¢
DJT Donald J. Trump	2.3% ↓ -0.9%	1.7%	$71.7K	Kalshi 2.5% 2–3¢ Vol $223	Polymarket 2.3% 2.2–2.4¢ Vol $71.5K	Gemini 4.0% 0–8¢ Vol $0	OG — —
PB Pete Buttigieg	1.9% ↓ -0.7%	2.2%	$13.7K	Kalshi 2.5% 2–3¢ Vol $102	Polymarket 1.8% 1.8–1.9¢ Vol $13.6K	Gemini — —	OG 4.0% 4¢
DTR Dwayne 'The Rock' Johnson	1.7% ↓ -0.4%	—	$100.2K	Kalshi — —	Polymarket 1.7% 1.6–1.8¢ Vol $100.2K	Gemini — —	OG — —
RD Ron DeSantis	1.7% ↑ +0.2%	2.4%	$22.1K	Kalshi 2.5% 2–3¢ Vol $1	Polymarket 1.7% 1.6–1.7¢ Vol $22.1K	Gemini — —	OG 4.0% 4¢
TC Tucker Carlson	1.7% ↑ +0.1%	—	$30.5K	Kalshi — —	Polymarket 1.7% 1.6–1.7¢ Vol $30.5K	Gemini — —	OG — —
AB Andy Beshear	1.5% ↓ -0.3%	1.5%	$103.3K	Kalshi 1.5% 1–2¢ Vol $246	Polymarket 1.6% 1.5–1.6¢ Vol $103.0K	Gemini — —	OG 3.0% 3¢
JBP J.B. Pritzker	1.4% — +0.0%	2.7%	$2.1K	Kalshi 2.5% 2–3¢ Vol $170	Polymarket 1.4% 1.3–1.4¢ Vol $1.9K	Gemini — —	OG 4.0% 4¢
IT Ivanka Trump	1.3% — +0.0%	—	$25.8K	Kalshi — —	Polymarket 1.3% 1.2–1.3¢ Vol $25.8K	Gemini — —	OG — —
MO Michelle Obama	1.3% ↑ +0.5%	—	$13.9K	Kalshi — —	Polymarket 1.3% 1.2–1.3¢ Vol $13.9K	Gemini — —	OG — —
NH Nikki Haley	1.3% ↑ +0.5%	3.5%	$294.3K	Kalshi 0.5% 0–1¢ Vol $1	Polymarket 1.3% 1.2–1.3¢ Vol $294.3K	Gemini — —	OG 4.0% 4¢
EM Elon Musk	1.2% ↑ +0.1%	—	$852.0K	Kalshi — —	Polymarket 1.2% 1.1–1.2¢ Vol $852.0K	Gemini — —	OG — —
JD Jamie Dimon	1.1% ↑ +0.4%	0.7%	$18.5K	Kalshi 0.5% 0–1¢ Vol $4	Polymarket 1.2% 1.1–1.2¢ Vol $18.5K	Gemini — —	OG — —
GW Gretchen Whitmer	1.1% ↓ -1.3%	2.9%	$64.2K	Kalshi 1.5% 1–2¢ Vol $80	Polymarket 1.1% 1–1.1¢ Vol $64.1K	Gemini — —	OG 4.0% 4¢
TG Tulsi Gabbard	1.0% ↑ +0.3%	3.5%	$418.8K	Kalshi 0.5% 0–1¢ Vol $149	Polymarket 1.1% 1–1.1¢ Vol $418.6K	Gemini — —	OG 4.0% 4¢
SAS Stephen A. Smith	1.0% ↑ +0.1%	0.5%	$101.6K	Kalshi 1.5% 1–2¢ Vol $51	Polymarket 1.0% 0.9–1¢ Vol $101.6K	Gemini — —	OG — —
GA Greg Abbott	1.0% ↑ +0.2%	0.4%	$43.9K	Kalshi 0.5% 0–1¢ Vol $0	Polymarket 1.0% 0.9–1¢ Vol $43.9K	Gemini — —	OG — —
WM Wes Moore	1.0% ↓ -0.6%	0.5%	$294.9K	Kalshi 1.5% 1–2¢ Vol $7	Polymarket 1.0% 0.9–1¢ Vol $294.9K	Gemini — —	OG — —
GY Glenn Youngkin	0.9% ↑ +0.1%	2.2%	$214.2K	Kalshi 1.5% 1–2¢ Vol $29	Polymarket 0.9% 0.8–0.9¢ Vol $214.2K	Gemini — —	OG 3.0% 3¢
DJT Donald J. Trump Jr.	0.9% ↓ -0.4%	0.6%	$42.9K	Kalshi 1.5% 1–2¢ Vol $2	Polymarket 0.9% 0.8–0.9¢ Vol $42.9K	Gemini — —	OG — —
TW Tim Walz	0.9% ↑ +0.1%	2.5%	$146.1K	Kalshi 0.5% 0–1¢ Vol $0	Polymarket 0.9% 0.8–0.9¢ Vol $146.1K	Gemini — —	OG 3.0% 3¢
VR Vivek Ramaswamy	0.9% ↓ -0.1%	2.5%	$518.1K	Kalshi 0.5% 0–1¢ Vol $24	Polymarket 0.9% 0.8–0.9¢ Vol $518.1K	Gemini — —	OG 3.0% 3¢
ZM Zohran Mamdani	0.9% — +0.0%	—	$112.1K	Kalshi — —	Polymarket 0.9% 0.8–0.9¢ Vol $112.1K	Gemini — —	OG — —
KK Kim Kardashian	0.8% ↓ -0.1%	—	$197.5K	Kalshi — —	Polymarket 0.8% 0.7–0.8¢ Vol $197.5K	Gemini — —	OG — —
LJ LeBron James	0.8% ↓ -0.1%	—	$198.8K	Kalshi — —	Polymarket 0.8% 0.7–0.8¢ Vol $198.8K	Gemini — —	OG — —

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
JDV J.D. Vance	Kalshi → Polymarket	Buy @ K 18¢	Sell @ P 20.2¢	+2.20%	+2.02%	Yes
JS Josh Shapiro	Polymarket → Kalshi	Buy @ P 2.5¢	Sell @ K 4¢	+1.50%	+1.43%	No
MR Marco Rubio	Polymarket → Kalshi	Buy @ P 16.3¢	Sell @ K 17¢	+0.70%	+0.53%	No
JBP J.B. Pritzker	Polymarket → Kalshi	Buy @ P 1.4¢	Sell @ K 2¢	+0.60%	+0.53%	No
RD Ron DeSantis	Polymarket → Kalshi	Buy @ P 1.7¢	Sell @ K 2¢	+0.30%	+0.23%	No
NH Nikki Haley	Kalshi → Polymarket	Buy @ K 1¢	Sell @ P 1.2¢	+0.20%	+0.13%	No
PB Pete Buttigieg	Polymarket → Kalshi	Buy @ P 1.9¢	Sell @ K 2¢	+0.10%	+0.03%	No
GY Glenn Youngkin	Polymarket → Kalshi	Buy @ P 0.9¢	Sell @ K 1¢	+0.10%	+0.03%	No
DJT Donald J. Trump Jr.	Polymarket → Kalshi	Buy @ P 0.9¢	Sell @ K 1¢	+0.10%	+0.03%	No
JD Jamie Dimon	Kalshi → Polymarket	Buy @ K 1¢	Sell @ P 1.1¢	+0.10%	+0.03%	No
AOC Alexandria Ocasio-Cortez	Polymarket → Kalshi	Buy @ P 5¢	Sell @ K 5¢	+0.00%	-0.07%	No
TG Tulsi Gabbard	Kalshi → Polymarket	Buy @ K 1¢	Sell @ P 1¢	+0.00%	-0.07%	No
SAS Stephen A. Smith	Polymarket → Kalshi	Buy @ P 1¢	Sell @ K 1¢	+0.00%	-0.07%	No
WM Wes Moore	Polymarket → Kalshi	Buy @ P 1¢	Sell @ K 1¢	+0.00%	-0.07%	No
GW Gretchen Whitmer	Polymarket → Kalshi	Buy @ P 1.1¢	Sell @ K 1¢	-0.10%	-0.17%	No
GA Greg Abbott	Kalshi → Polymarket	Buy @ K 1¢	Sell @ P 0.9¢	-0.10%	-0.17%	No
GN Gavin Newsom	Polymarket → Kalshi	Buy @ P 17.2¢	Sell @ K 17¢	-0.20%	-0.37%	No
TW Tim Walz	Kalshi → Polymarket	Buy @ K 1¢	Sell @ P 0.8¢	-0.20%	-0.27%	No
VR Vivek Ramaswamy	Kalshi → Polymarket	Buy @ K 1¢	Sell @ P 0.8¢	-0.20%	-0.27%	No
KH Kamala Harris	Polymarket → Kalshi	Buy @ P 3.3¢	Sell @ K 3¢	-0.30%	-0.37%	No
DJT Donald J. Trump	Polymarket → Kalshi	Buy @ P 2.4¢	Sell @ K 2¢	-0.40%	-0.47%	No
AB Andy Beshear	Kalshi → Polymarket	Buy @ K 2¢	Sell @ P 1.5¢	-0.50%	-0.57%	No

Outcome Diff

Outcome A	Outcome B	Venue	A Odds	B Odds	Diff	Strategy
JDV J.D. Vance	RD Ron DeSantis	Polymarket	A 20.3%	B 1.7%	+18.60%	Buy spread
JDV J.D. Vance	DTR Dwayne 'The Rock' Johnson	Polymarket	A 20.3%	B 1.7%	+18.55%	Buy spread
JDV J.D. Vance	PB Pete Buttigieg	Polymarket	A 20.3%	B 1.8%	+18.40%	Buy spread
JDV J.D. Vance	DJT Donald J. Trump	Polymarket	A 20.3%	B 2.3%	+17.95%	Buy spread
JDV J.D. Vance	JS Josh Shapiro	Polymarket	A 20.3%	B 2.5%	+17.80%	Buy spread
JDV J.D. Vance	KH Kamala Harris	Polymarket	A 20.3%	B 3.3%	+17.00%	Buy spread
JDV J.D. Vance	DJT Donald J. Trump	Gemini	A 20.5%	B 4.0%	+16.50%	Buy spread
GN Gavin Newsom	RD Ron DeSantis	Polymarket	A 17.2%	B 1.7%	+15.50%	Buy spread
GN Gavin Newsom	DTR Dwayne 'The Rock' Johnson	Polymarket	A 17.2%	B 1.7%	+15.45%	Buy spread
JDV J.D. Vance	AOC Alexandria Ocasio-Cortez	Polymarket	A 20.3%	B 5.0%	+15.30%	Buy spread
GN Gavin Newsom	PB Pete Buttigieg	Polymarket	A 17.2%	B 1.8%	+15.30%	Buy spread
JDV J.D. Vance	DJT Donald J. Trump	Kalshi	A 17.5%	B 2.5%	+15.00%	Buy spread
JDV J.D. Vance	PB Pete Buttigieg	Kalshi	A 17.5%	B 2.5%	+15.00%	Buy spread
JDV J.D. Vance	RD Ron DeSantis	Kalshi	A 17.5%	B 2.5%	+15.00%	Buy spread
JDV J.D. Vance	JBP J.B. Pritzker	Kalshi	A 17.5%	B 2.5%	+15.00%	Buy spread
GN Gavin Newsom	DJT Donald J. Trump	Kalshi	A 17.5%	B 2.5%	+15.00%	Buy spread
GN Gavin Newsom	PB Pete Buttigieg	Kalshi	A 17.5%	B 2.5%	+15.00%	Buy spread
GN Gavin Newsom	RD Ron DeSantis	Kalshi	A 17.5%	B 2.5%	+15.00%	Buy spread
GN Gavin Newsom	JBP J.B. Pritzker	Kalshi	A 17.5%	B 2.5%	+15.00%	Buy spread
MR Marco Rubio	DJT Donald J. Trump	Kalshi	A 17.5%	B 2.5%	+15.00%	Buy spread
MR Marco Rubio	PB Pete Buttigieg	Kalshi	A 17.5%	B 2.5%	+15.00%	Buy spread
MR Marco Rubio	RD Ron DeSantis	Kalshi	A 17.5%	B 2.5%	+15.00%	Buy spread
MR Marco Rubio	JBP J.B. Pritzker	Kalshi	A 17.5%	B 2.5%	+15.00%	Buy spread
GN Gavin Newsom	DJT Donald J. Trump	Polymarket	A 17.2%	B 2.3%	+14.85%	Buy spread
GN Gavin Newsom	JS Josh Shapiro	Polymarket	A 17.2%	B 2.5%	+14.70%	Buy spread
MR Marco Rubio	RD Ron DeSantis	Polymarket	A 16.2%	B 1.7%	+14.55%	Buy spread
MR Marco Rubio	DTR Dwayne 'The Rock' Johnson	Polymarket	A 16.2%	B 1.7%	+14.50%	Buy spread
MR Marco Rubio	PB Pete Buttigieg	Polymarket	A 16.2%	B 1.8%	+14.35%	Buy spread
JDV J.D. Vance	KH Kamala Harris	Kalshi	A 17.5%	B 3.5%	+14.00%	Buy spread
GN Gavin Newsom	KH Kamala Harris	Kalshi	A 17.5%	B 3.5%	+14.00%	Buy spread

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).

Gemini: Public Prediction Markets + ticker endpoints (best bid/ask + last + 24H USD volume when available).

OG: Public OG contracts endpoint (Yes/No chance from contract data; no provider 24H volume field in this payload).

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.