Race Overview

Sen. Ed Markey advanced from the Democratic primary in the Massachusetts U.S. Senate race on Sept. 1, 2026, according to unofficial results. The Republican primary, which had one candidate, was still counting as of the same date. The general election is set for Nov. 3, 2026, with 12 candidates across parties on the ballot.

Markey's pre-primary polling average stood at 56 percent, against challenger Rep. Seth Moulton's 35 percent, with 9 percent undecided, according to a 270toWin aggregate of 41 polls as of Aug. 29, 2026. The margin in that average was 21 points.

Sen. Markey, 80, the incumbent was viewed as the more progressive candidate. Moulton, 47, is viewed as moderate. In this Senate race, voters prioritized left-leaning values over the candidates’ ages.

Moulton, in a primary night concession speech covered by WBUR, said: "I spoke to Senator Markey tonight and pledged that I will do everything I can to help him win re-election in November, to ensure a Democrat represents the state we both love."

PAC and SuperPAC Spending in the Primary

Seven independent expenditure filings were recorded in the primary, all directed at the Democratic contest. Total outside spending came to $2,112,364.93, with $2,112,274.93 in opposition spending and $90 in support spending.

Advance Progress, a super PAC, accounted for $1,482,274.93 — all opposing Markey — spread across three transactions: $650,000 in digital media advertising on May 29, $800,000 in digital media advertising on June 12, and $32,274.93 for media production on May 13, all paid to vendors Uplift and Village Square LLC.

Commonwealth Together PAC spent $630,000 opposing Moulton across two digital advertising buys: $350,000 on April 1 and $280,000 on May 6, both paid to Authentic Campaigns.

GiveGreen United Action spent $80 supporting Markey via email messaging in December 2025. Sierra Club Independent Action spent $10 supporting Markey via a website endorsement in February 2026.

No general election independent expenditure filings appear in the records for this race. The data also shows pending notice totals that have not yet been restated in periodic filings, as of Sept. 2, 2026.

Party Leadership Reaction

Sen. Elizabeth Warren endorsed Markey. She appeared at a get-out-the-vote rally in Dorchester on Aug. 29, 2026, alongside Sen. Bernie Sanders (I-Vt.) and Rep. Ayanna Pressley (D-Mass.), according to the Boston Herald.

Sanders said at the rally: "Status quo politics and status quo policies are not working. We have to fight for an agenda that works for all, not just the few. That's exactly why we need to send Ed Markey back to the United States Senate."

Rep. Alexandria Ocasio-Cortez (D-N.Y.) endorsed Markey on Aug. 20, 2026, stating: "His work is an inspiration to many of us who are committed to building a better future for all, and that's why I'm proud to endorse him," per The Hill.

Predictions

The Cook Political Report rated the race "Solid Democratic" as of Aug. 20, 2026. Sabato's Crystal Ball carried the same rating as of Aug. 26, and Inside Elections as of Aug. 6. The 270toWin consensus rating, as of Aug. 31, also showed "Solid Democratic." No forecaster moved the race from that tier heading into or following the primary.

On Kalshi, as of Sept. 2, 2026, the Democratic probability stood at 98.7 percent and the Republican probability at 1.3 percent, on $8,845 in total volume. The low volume means individual trades can move the price meaningfully.

The forecaster ratings and prediction market odds were aligned ahead of the primary, and the primary result — Markey advancing as the Democratic nominee — did not alter either. Heading into November, the race carries the same ratings it held before the primary, with no competitive signals from outside spending, forecasters, or markets.

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