2028 Party Nominees — Democratic and Republican primaries

2028 Democratic and Republican primaries—cross-exchange Categorical view

Polymarket and Kalshi both list deep Categorical books on each party's 2028 presidential nominee, and together they're the highest-24h-volume durable politics anchor on prediction markets right now—Polymarket carries $1.5M+/24h on the Democratic field and $1.2M+/24h on the Republican, with Kalshi running mid-six-figures on each as the cross-exchange counterweight.

This workspace surfaces both party fields side-by-side on both exchanges so the cross-exchange spread on any single contender becomes the cleanest signal. Polymarket's books tend to be deeper and faster-moving; Kalshi's are smaller but useful as a sanity check on whether a Polymarket move is a real probability shift or a single-book liquidity event. The full 2028 presidential winner workspace lives at predictions.qwidgets.com/w/2028-presidential-election; this one is the primary-cycle deep dive.

Democratic nominee—Polymarket and Kalshi side-by-side

Polymarket's democratic-presidential-nominee-2028 is the deepest book on the field ($1.5M+/24h); Kalshi's KXPRESNOMD-28 adds the cross-exchange spread ($456k/24h). Both pies show the full candidate field—watch the cross-exchange gap on any front-runner contender.

Republican nominee—open field or Vance lock?

Polymarket's republican-presidential-nominee-2028 ($1.2M+/24h) and Kalshi's KXPRESNOMR-28 ($85k/24h) both list the Republican field. The 2028 GOP nominee market has historically priced Vance and Trump-family successors high; watch for divergence between the two books on lower-ranked contenders.

Probability timeline—Polymarket Democratic field into 2028

The price trajectory of Polymarket's Dem nominee book over time shows how the field has consolidated (or fragmented) as the cycle progresses. Use it to track whether any candidate's lead is sustained vs. a single-day liquidity spike.

• The cross-exchange spread on any single front-runner is the cleanest signal. Polymarket's book typically leads in liquidity; Kalshi's is the sanity-check counterweight. Persistent spread = real price disagreement; transient spread = liquidity-driven.
• Dem vs Rep volume asymmetry is itself a tell. When the Democratic nominee book trades 30%+ heavier than the Republican, the markets are pricing more uncertainty into the Dem field; the reverse usually signals a quiet pre-primary cycle.
• VP markets (Kalshi KXVPRESNOMD-28) trade much thinner—useful as a sentiment indicator on who's in the Dem ticket conversation, but not deep enough for narrative weight.
• Settlement is November 7, 2028. This is a 2.5-year durable anchor; expect the field to compress meaningfully as state-level primary results land in early 2028.
• The general election workspace (2028-presidential-election) covers the head-to-head winner pie. Use the two together for the full 2028 picture.