The 2028 Democratic nomination is the most heavily traded market in politics, and it has no favourite. As of September 21, 2026, Alexandria Ocasio-Cortez leads on Polymarket at 18.4¢, Jon Ossoff sits a cent behind at 17.2¢, and Gavin Newsom trails at 15.7¢. Three candidates within three points of each other, none above one-in-five, more than two years before a single primary vote.
That makes the 2028 Democratic nominee odds unusual. Most nomination markets this far out have a clear frontrunner who gets priced at 30% or 40% and then fades. This one has a crowded top tier, a second tier with a former nominee in it, and a long tail of governors and senators whose chances depend on elections that have not happened yet.
Polymarket's version of this market has traded about $1.28 billion, the most of anything we track. Kalshi's has traded about 222 million contracts. Here is the full picture, where the two venues disagree, and what a nomination contract actually pays for when it will not settle until the summer of 2028.
| Candidate | Current role | Polymarket | Kalshi (bid / ask) | Gap |
|---|---|---|---|---|
| Alexandria Ocasio-Cortez | US Representative, New York | 18.4¢ | 15¢ / 16¢ | Polymarket +3.0 |
| Jon Ossoff | US Senator, Georgia | 17.2¢ | 16¢ / 17¢ | Polymarket +0.7 |
| Gavin Newsom | Governor of California | 15.7¢ | 13¢ / 14¢ | Polymarket +2.1 |
| Kamala Harris | Former Vice President | 8.9¢ | 7.9¢ / 8.1¢ | Polymarket +0.9 |
| Josh Shapiro | Governor of Pennsylvania | 5.7¢ | 4.6¢ / 4.7¢ | Polymarket +1.0 |
| Pete Buttigieg | Former Transportation Secretary | 5.1¢ | 5.2¢ / 5.3¢ | Even |
| Mark Kelly | US Senator, Arizona | 3.0¢ | 3.9¢ / 4.2¢ | Kalshi +1.0 |
| Andy Beshear | Governor of Kentucky | 2.5¢ | 3.5¢ / 3.7¢ | Kalshi +1.1 |
| James Talarico | Texas Senate nominee | 2.5¢ | 1.8¢ / 1.9¢ | Polymarket +0.6 |
| Rahm Emanuel | Former Ambassador to Japan | 1.8¢ | 3.0¢ / 3.1¢ | Kalshi +1.2 |
| Wes Moore | Governor of Maryland | 1.8¢ | 2.2¢ / 2.3¢ | Kalshi +0.5 |
| Ro Khanna | US Representative, California | 1.4¢ | 1.8¢ / 1.9¢ | Kalshi +0.5 |
| J.B. Pritzker | Governor of Illinois | 1.2¢ | 1.7¢ / 2.0¢ | Kalshi +0.6 |
Prices come from PredictReport's tracker on the morning of September 21, 2026; the live 2028 Democratic nominee page updates every ten minutes. Each contract pays $1 if that person is the Democratic nominee, so the price in cents is the market's probability. Our explainer on prediction market odds converts these into the American odds a sportsbook would show.
The Three-Way Race at the Top
Ocasio-Cortez, Ossoff and Newsom together account for a bit over half the probability in the market. That is a statement about how open the field is: the market thinks there is a roughly even chance the nominee is someone other than these three.
Alexandria Ocasio-Cortez leads at 18.4¢ on Polymarket, but Kalshi prices her lower at 15–16¢, the widest gap among the leading candidates. Her price has drifted down through September, from 19.8¢ on September 1 to a low of 17.6¢ on September 12, before recovering slightly. At 18.4¢, a $100 position pays out about $543 if she is nominated.
Jon Ossoff is the most interesting case on the board, because his nomination price is tied to another market. He is on the ballot in Georgia this November, and Kalshi prices his re-election at 93–94¢. A loss would end his 2028 case overnight; a comfortable win would make him the rare candidate with a fresh statewide victory in a swing state. His nomination price has risen from 16.2¢ to 17.2¢ this month, and the two venues agree closely on him. Our 2026 midterm election odds cover the Georgia race.
Gavin Newsom is the most volatile of the three. His price ranged from 12.0¢ on September 13 to 18.6¢ on September 15 — more than six points in two days — before settling at 15.7¢. That kind of swing in a market this deep means large orders are moving through it. For a trader, volatility is opportunity only if you understand the book; our guide to prediction market liquidity explains why the same headline price can mean very different things.
Kamala Harris and the Second Tier
At 8.9¢ on Polymarket and 8¢ on Kalshi, Kamala Harris is the market's fourth choice. She is the only candidate in the field who has already been the Democratic nominee, having replaced Joe Biden on the 2024 ticket. The market is pricing a real but limited chance that the party returns to her, and her price has firmed from 7.7¢ to 8.9¢ this month.
Josh Shapiro, at 5.7¢, is the second tier's clearest case. He is the governor of Pennsylvania and faces re-election this November, which gives him the same kind of test Ossoff faces. Pete Buttigieg, at 5.1¢, is the one leading candidate on whom both venues agree almost exactly.
Mark Kelly and Andy Beshear are where Kalshi's pricing diverges most from Polymarket's in this tier. Kalshi puts both about a point higher — Kelly at roughly 4¢ against Polymarket's 3¢, Beshear at 3.6¢ against 2.5¢. On contracts this cheap, a one-point gap is a 30–40% difference in implied probability, which is larger than it looks — our odds converter shows what each price means as American or decimal odds. We come back to what that means for trading below.
The Long Shots Worth Understanding
Below 3¢, the market is a list of plausible scenarios rather than a ranking. The long shots are worth knowing because some of them are linked to near-term events.
James Talarico is the Democratic nominee for Senate in Texas, and Kalshi gives him a 59–60% chance of winning that race in November. A Democrat winning a Texas Senate race for the first time since 1988 would transform his profile, which is presumably why he trades at 2.5¢ on Polymarket already. Wes Moore faces re-election in Maryland; J.B. Pritzker is seeking a third term in Illinois. Their 2028 prices will move on those results.
Rahm Emanuel is the long shot the two venues disagree on most. Kalshi prices him at 3¢, Polymarket at 1.8¢. The pattern across the table is consistent: Polymarket prices the three leaders higher, while Kalshi prices older and more establishment names higher. The two venues have different users — Polymarket settles in USDC on Polygon and draws heavily from crypto traders, while Kalshi settles in dollars and draws a broader US retail base — and the gaps look like different crowds rather than noise. Our Polymarket review and Kalshi review describe each venue's user base.
The celebrity entry is Dwayne Johnson at 1.1¢ on Polymarket, where Kalshi's bid is 0¢ and its ask just 0.2¢. A contract with no buyers on one venue is not a price anyone can trade against; it is a market nobody is standing behind.
How the Democratic Odds Moved in September
PredictReport has tracked both venues continuously since September 1. The month has been a slow rotation rather than a shake-up.
| Candidate | Sept 1 | Sept 21 | Change | September range |
|---|---|---|---|---|
| Alexandria Ocasio-Cortez | 19.8¢ | 18.4¢ | −1.4 | 17.6¢ – 19.8¢ |
| Jon Ossoff | 16.2¢ | 17.2¢ | +1.0 | 15.6¢ – 17.2¢ |
| Gavin Newsom | 14.5¢ | 15.7¢ | +1.2 | 12.0¢ – 18.6¢ |
| Kamala Harris | 7.7¢ | 8.9¢ | +1.2 | 7.7¢ – 9.7¢ |
| Josh Shapiro | 5.1¢ | 5.7¢ | +0.6 | 5.0¢ – 6.6¢ |
Polymarket prices shown. The leaders are converging: the gap between first and third has narrowed from 5.3 points to 2.7. In a market this far from resolution, that is the typical pattern — information arrives slowly, and prices mean-revert toward a crowded field until something decisive happens. The live market page shows today's prices against these.
Where Polymarket and Kalshi Disagree
The largest gap in the market is Ocasio-Cortez at three points: 18.4¢ on Polymarket against a 15.5¢ midpoint on Kalshi. Is that an arbitrage? Not on the current quotes. To lock a profit, you would buy her YES on Kalshi at the 16¢ ask and her NO on Polymarket at 81.9¢ — one minus Polymarket's 18.1¢ bid. That costs 97.9¢ before fees for a contract pair that pays exactly $1. After Kalshi's fee and Polymarket's taker fee, the margin disappears.
That is why our arbitrage scanner does not flag this market today, even though the midpoints differ by three points. The scanner looks at executable bid and ask prices on both venues, nets out fees, and only shows a trade when the combined cost is meaningfully under $1. Midpoint gaps are interesting; executable gaps are money. Our arbitrage guide explains the difference in detail.
The gaps still matter if you are only buying one side. Someone bullish on Ocasio-Cortez should buy on Kalshi at 16¢ rather than Polymarket at 18.8¢ — the same payout for 15% less money. Someone bullish on Beshear or Emanuel should buy on Polymarket. Checking both venues before every purchase is the simplest edge in this market, and it costs nothing.
Why Early Frontrunners Rarely Hold
Nomination markets two years out have a poor record of naming the eventual winner, and the reason is structural. Most of the information that decides a nomination — who runs, who raises money, who wins the first contests — does not exist yet.
The history is humbling. Hillary Clinton led the 2008 Democratic field for most of 2007 and lost the nomination to Barack Obama. Jeb Bush was the early establishment favourite for 2016 and was out of the race by February. In February 2020, after the first contests, Bernie Sanders became the betting favourite for the Democratic nomination; Joe Biden won South Carolina and took it. And in 2024, the presumptive Democratic nominee withdrew in July and was replaced by a candidate who had not won a single primary.
The lesson is not that the market is wrong. A leader at 18% is a market that already knows it does not know. The lesson is that anyone paying 18¢ today is buying two years of uncertainty, and should size the position accordingly. Our history of how prediction markets evolved covers earlier election markets, and our guide to prediction market accuracy explains how well long-dated prices tend to perform.
The Party Market: Democrats Favoured for 2028
A separate market asks which party wins the 2028 presidential election, and it currently shows the biggest cross-venue gap of any political market we track. Polymarket prices the Democrats at 64.5¢; Kalshi at 58–59¢. That six-point gap has persisted, and the Democratic price on Polymarket has risen from 59.5¢ on September 1, peaking at 68.5¢ on September 14.
This one is a genuine arbitrage. Buy the Democratic side on Kalshi at 59¢ and the Republican side on Polymarket at 36¢, and you hold a pair that pays $1 whoever wins, for 95¢ before fees. After fees, our scanner calculates a 2.4% return. The catch is time: the money is locked until November 2028, so the annualised return is about 0.8%. Kalshi pays roughly 4% a year on idle cash, which means the arbitrage currently earns less than leaving the money uninvested on Kalshi. The live party market shows the current gap.
That comparison — arbitrage return against the yield on idle cash — is the one most traders skip. A locked profit is only worth taking if it beats what the capital would earn doing nothing.
How the Nomination Market Resolves
A nomination contract resolves on who the party formally nominates, not on who wins the most primaries or who leads the polls in spring 2028. That distinction has mattered before: in 2024, the Democratic nominee was chosen by delegates after the presumptive nominee withdrew, and every contract on the eventual nominee paid out on that basis.
Read the specific rules on each venue before buying. They define the resolution source, what happens if a nominee withdraws after the convention, and when the market settles. Two contracts that look identical on Polymarket and Kalshi can use slightly different language, which is the main risk in holding opposite sides across venues. Our explainer on how prediction markets resolve covers what to check.
How to Trade the 2028 Democratic Nomination
For most US traders, Kalshi is the regulated default: CFTC-regulated, dollars in and out, and roughly 4% on idle cash. Polymarket offers the deepest book in this market by far and settles in USDC. If you are choosing between them, Polymarket vs Kalshi compares them in detail, and our ranking of the best prediction market apps covers the wider field. If you are new to the mechanics, start with how prediction markets work.
Three practical rules apply to any long-dated political contract. Use limit orders rather than crossing the spread, because on cheap contracts the spread is a large share of the price — our guide to limit orders explains how. Size for two years of volatility, not for your conviction today. And remember that fees apply on entry and on any exit before resolution; our market fee calculator shows the cost at any price on either venue.
Profits are taxable when realised, whether or not you withdraw them, and Kalshi issues a 1099-MISC; see our prediction market tax guide. Political contracts sit at the centre of the legal fight over prediction markets, so check our legal guide for your state.
Frequently Asked Questions
Who is the favorite for the 2028 Democratic nomination?
There is no clear favourite. As of September 21, 2026, Alexandria Ocasio-Cortez leads on Polymarket at 18.4¢, with Jon Ossoff at 17.2¢ and Gavin Newsom at 15.7¢. Kalshi prices Ossoff and Ocasio-Cortez roughly level at 15–17¢.
What are Gavin Newsom's odds of winning the 2028 nomination?
About 15–16% on Polymarket and 13–14% on Kalshi. His price has been the most volatile of the leaders, ranging from 12¢ to 18.6¢ during September 2026.
Is Kamala Harris running in 2028?
She has not been ruled out by the market, which prices her nomination at about 8–9¢ on both venues. That makes her the fourth choice, behind Ocasio-Cortez, Ossoff and Newsom.
Why are Polymarket and Kalshi odds different for the Democratic nomination?
The venues have different users and settle in different currencies, so their order books drift apart. Polymarket prices the top three higher; Kalshi prices establishment names like Rahm Emanuel and Andy Beshear higher. See Polymarket vs Kalshi.
Can you arbitrage the 2028 Democratic nominee market?
Not on current prices. The biggest gap, on Ocasio-Cortez, disappears once you use executable bid and ask prices and pay fees. Our arbitrage scanner shows any market where the gap survives fees.
When does the 2028 Democratic nomination market pay out?
When the party formally nominates its candidate at the 2028 convention. The capital is locked for roughly two years, so compare any expected return with the roughly 4% Kalshi pays on idle cash.
How accurate are early presidential nomination odds?
Not very, and they are not designed to be. Early frontrunners like Hillary Clinton in 2008 and Jeb Bush in 2016 lost. A leader priced below 20% is a market signalling that the race is wide open.
Which party is favored to win the 2028 presidential election?
The Democrats, at 64.5¢ on Polymarket and 58–59¢ on Kalshi. That six-point gap is one of the largest between the two venues on any political market.
