Short Answer

The model sees potential mispricing: Katherine Clark at 99.8% model vs 88.0% market. This suggests strong evidence of her incumbency, significant financial advantage, and lack of certified primary challengers for the MA-05 Democratic nomination.

1. Executive Verdict

  • Katherine Clark holds over $2.29 million cash-on-hand for Q1 2026.
  • Clark leads certified primary challengers by 48-54 points in polls.
  • Jonathan Paz and Tarik Samman are not certified primary candidates.
  • Officially certified challengers poll extremely poorly with minimal resources.
  • No evidence suggests strong support or momentum for any other candidate.

Who Wins and Why

Outcome Market Model Why
Katherine Clark 88.0% 99.8% Katherine Clark is the incumbent with a significant financial advantage and substantial polling leads.
Jonathan Paz 12.0% 0.1% Jonathan Paz is not an officially certified Democratic candidate for the MA-05 primary.
Tarik Samman 4.0% 0.1% Tarik Samman is not an officially certified Democratic candidate for the MA-05 primary.

2. Market Behavior & Price Dynamics

Historical Price (Probability)

Outcome probability
Date
Based on the provided data, the prediction market for the 2026 MA-05 Democratic nominee has exhibited a stable, sideways trend since its inception. The contract has consistently traded at a high probability, opening at 89.0% and currently priced at 88.0%. The price has remained within a narrow 7-point range, between a low of 82.0% and a high of 89.0%. This indicates that market participants have a very high and unwavering confidence in a specific outcome. There have been no significant price spikes or drops; the fluctuations have been minor and gradual. Given the absence of any provided news or external context, these small price adjustments cannot be attributed to any specific event.
The trading volume in this market has been exceptionally low, with only 112 contracts traded in total. This low level of activity suggests a lack of broad market interest or conviction and may indicate low liquidity. While the price is stable, the low volume means that the current price reflects the opinion of a very small number of traders. The 89.0% level has acted as a point of resistance where the price started, while 82.0% has served as a clear support level. Overall, the chart reflects a strong and stable market sentiment, pricing in a particular candidate as the overwhelming favorite for the nomination, with no new information emerging to challenge this initial assessment.

3. Market Data

View on Kalshi →

Contract Snapshot

This market resolves to Yes if Katherine Clark wins the Democratic Party nomination for the 2026 MA-05 House seat, with the outcome verified by the Democratic Party. If she does not secure the nomination, it resolves to No. The market opens on December 27, 2025, at 10:00 AM EST, and closes either upon the nomination outcome or by September 15, 2027, at 10:00 AM EDT, with the event noted as mutually exclusive.

Available Contracts

Market options and current pricing

Outcome bucket Yes (price) No (price) Last trade probability
Katherine Clark $0.88 $0.15 88%
Jonathan Paz $0.10 $0.94 12%
Tarik Samman $0.04 $0.99 4%

Market Discussion

Traders overwhelmingly anticipate Katherine Clark, the incumbent, to be the Democratic nominee for MA-05, with her market probability holding at 88%. Those betting "Yes" view her nomination as a "sure thing" and a low-risk investment offering a decent annual return for the long wait until September 2026. There are no substantive arguments against Clark's nomination in the discussion, with one "No" trade being an admitted geographical error rather than a genuine prediction.

4. What is Katherine Clark's Current Campaign Cash-on-Hand?

Latest Cash-on-Hand$572,208.52 (as of March 31, 2024) [^]
Data for Net Change (Nov 2024 - Q2 2025)Not yet publicly available [^]
2026 Run for Different OfficeNo public statements or committee transfers identified [^]
Katherine Clark's campaign reported over $572,000 cash-on-hand as of March 2024. Her principal campaign committee, "Katherine Clark for Congress" (FEC Committee ID: C00541888), reported a cash-on-hand balance of $572,208.52 as of March 31, 2024 [^]. The net change in cash-on-hand between the November 2024 election and the Q2 2025 filing deadline cannot be calculated at this time. This is because the necessary data from the Q4 2024 report, due January 31, 2025, and the Q2 2025 report, due July 15, 2025, covers future periods and is not yet publicly available [^].
No public statements or transfers indicate a 2026 campaign for a different office. A review of available sources indicates no public statements from Katherine Clark or committee transfers suggesting a run for a different office in 2026. Her principal campaign committee, "Katherine Clark for Congress," is designated for her current House seat (H4MA05084) [^]. Furthermore, her joint fundraising committee, the "Katherine Clark Majority Fund" (FEC Committee ID: C00831669), reported activities through December 31, 2023, without any disbursements indicating a campaign for an alternative position [^]. No such announcements were identified in her official press releases or general candidate overviews within the provided materials [^].

5. Does Jonathan Paz Have Progressive Endorsements for MA-05?

Candidate's RaceJonathan Paz running in MA-05 Democratic primary [^]
OpponentIncumbent House Minority Whip Katherine Clark [^]
Progressive EndorsementsNo disclosed formal endorsements from Justice Democrats, Our Revolution, or PCCC [1-9] [^]
Jonathan Paz challenges an incumbent for Massachusetts's 5th Congressional District. Jonathan Paz has announced his primary bid for the Massachusetts 5th Congressional District, seeking to unseat incumbent House Minority Whip Katherine Clark [^]. A former city councilor, Paz positions his campaign, "Paz for the People," on championing grassroots and progressive issues [^]. His campaign emphasizes a focus on matters important to progressive voters and aims to defeat a high-ranking incumbent [^].
No formal endorsements from key progressive organizations are confirmed. As of the end of 2025, research indicates Jonathan Paz's campaign has not secured formal endorsements from Justice Democrats, Our Revolution, or the Progressive Change Campaign Committee [^]. While Paz's campaign platform and his challenge to an incumbent suggest an alignment with progressive values [^], the available sources, including his campaign website [^], biographical information [^], news articles detailing his challenge to Representative Clark [^], and the official websites for the mentioned organizations [^], do not contain information confirming specific endorsements from these national progressive groups.

6. What is Katherine Clark's Q1 2026 Cash-on-Hand vs. Challengers' Funds?

Katherine Clark Q1 2026 Cash-on-Hand$2,298,638.27 [^]
Tarik Samman Q1 2026 Cash-on-Hand$68,105.12 [^]
Challengers' Combined Cash as % of Clark's2.96% (official Q1 2026 FEC filings) [^]
Katherine Clark's campaign reported significant cash-on-hand for Q1 2026. Her principal campaign committee, "Katherine Clark for Congress," reported a cash-on-hand balance of $2,298,638.27 during the Q1 2026 reporting period, which spans January 1 to March 31, 2026 [^]. Representative Clark is currently facing primary challenges in the MA-05 Democratic primary [^].
Primary challengers' combined cash-on-hand totaled over $68,000. For the same Q1 2026 period, challenger Tarik Samman's campaign reported $68,105.12 [^]. While Jonathan Paz is identified as another primary challenger [^], an official Q1 2026 FEC filing detailing his campaign's cash-on-hand was not available in the provided sources [^]. Consequently, Paz's reported cash-on-hand for this calculation is considered $0, making the combined cash-on-hand for the challengers $68,105.12.
Challengers' cash-on-hand represents a small fraction of Clark's. Based on Q1 2026 FEC filings, the combined cash-on-hand of primary challengers Tarik Samman and Jonathan Paz amounts to approximately 2.96% of Katherine Clark's principal campaign committee's cash-on-hand.

7. What Is Katherine Clark's Stance on the FY2026 NDAA?

Congressional Progressive Caucus Stance on FY2026 NDAAOfficially opposes [^]
Katherine Clark's Role on DoD Appropriations Act, 2026Democratic Whip [^]
Jonathan Paz Campaign Focus on Clark's Defense VotingNo information indicating it's a central theme [^]
Katherine Clark's future defense votes are not yet recorded. As legislative actions post-January 2025 have not yet occurred, Katherine Clark's final passage votes on major defense authorization or foreign military aid bills are not yet available [^]. However, the Congressional Progressive Caucus (CPC) has publicly declared its opposition to the National Defense Authorization Act (NDAA) for Fiscal Year 2026 [^]. Clark's role as Democratic Whip on the Department of Defense Appropriations Act, 2026 (H.R. 4016) suggests a supportive leadership position [^]. If Clark were to vote in favor of the FY2026 NDAA, her vote would diverge from the CPC's stated opposition [^]. The provided sources do not detail the CPC's collective stance on the Department of Defense Appropriations Act, 2026 (H.R. 4016) [^].
Challenger Jonathan Paz's campaign does not feature this issue. Information regarding challenger Jonathan Paz's campaign indicates that Katherine Clark's voting record on defense authorization or foreign military aid bills, or any divergence from the Congressional Progressive Caucus, is not a central theme in his official campaign advertising [^]. Paz's campaign website and primary bid announcement, cited in the research, do not include specific messaging on this particular issue [^].

8. Who Are the Candidates for MA-05 Primary and What Do Polls Show?

Certified Democratic Candidates (MA-05)Katherine Clark, Prisha Khan, Omar Saeed (as of April 30, 2026 filing deadline) [^]
Clark's Lead (90-day window before primary)No public polling found showing lead under 25 points against any single challenger [^]
Clark vs. Khan (Suffolk/Boston Globe Poll)Clark led Prisha Khan 65% to 11% (54-point lead) [^]
Katherine Clark faces two challengers in the MA-05 Democratic primary. As of the April 30, 2026 filing deadline, the officially certified Democratic candidates on the ballot for Massachusetts' 5th Congressional District election are incumbent Katherine Clark, Prisha Khan, and Omar Saeed [^]. Clark, who serves as the current House Minority Whip, is seeking re-election and is challenged by Prisha Khan, a community advocate from Cambridge, and Omar Saeed, a labor organizer based in Somerville [^].
No recent university polling shows Clark's lead under 25 points. Public polling from Massachusetts-based universities conducted within the final 90 days before the September 1, 2026 primary has not shown Clark's lead to be under 25 points against any single challenger [^]. A Suffolk University/Boston Globe poll published on April 15, 2026, which falls outside this 90-day window, indicated significant leads for Clark. In that poll, Clark led Omar Saeed 62% to 14%, a 48-point lead. Against Prisha Khan, Clark led 65% to 11%, a 54-point lead, with 24% undecided in both hypothetical matchups [^].

9. What Could Change the Odds

Key Catalysts

Catalyst analysis unavailable.

Key Dates & Catalysts

  • Expiration: September 15, 2027
  • Closes: September 15, 2027

10. Decision-Flipping Events

  • Trigger: Catalyst analysis unavailable.

12. Historical Resolutions

No historical resolution data available for this series.