2018 Midterm Election Betting Odds: Which Party Will Win the House and Senate?

2018 Midterm Election Betting Odds: Which Party Will Win the House and Senate? article feature image
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President Donald Trump. Credit USA Today

  • The 2018 Midterm Elections take place on Tuesday, Nov. 6
  • The betting market gives Democrats a 75% chance to win the House (-300 odds).
  • Republicans are listed as -550 favorites to retain control of the Senate (84.6% chance).
  • In Texas' Senate race, Ted Cruz is a big favorite (84.4% chance) to beat Beto O'Rourke (20.7% chance). In Missouri, Claire McCaskill is an underdog (45.5% chance) to retain her Senate seat vs. Josh Hawley (59.3% chance).

This Tuesday, tens of millions of Americans will head to the polls to cast their ballots in the 2018 Midterm Elections. At The Action Network, we've been tracking the betting odds for months, focusing on which party will win the House and the Senate, as well as individual state-by-state races.

As we enter the final 24-hour stretch before voting day, here's a look at how the betting market stands ahead of Nov. 6.

All odds current as of Sunday, Nov. 4.

2018 US House of Representatives Election- Majority Outcome

  • Democratic Majority: 75% chance (-300 odds)
  • Republican Majority: 33.3% chance (+200 odds)

Odds to win House Control 2018

  • Democrats: 71.5% chance (-251 odds)
  • Republicans: 34.6% chance (+189 odds)

The odds above from are in line with the rest of the market: At PredictIt, Democrats are trading at 70% to win the House; at Smarkets, Democrats sit at 68.97%.

Democrats have a 70% chance of controlling the House after the midterms, according to political prediction markets.

Disagree? Then make a wager @PredictIthttps://t.co/d3q6X9gcY4#Midterms2018#skininthegamepic.twitter.com/B0Zeht5blL

— PredictIt (@PredictIt) November 2, 2018


With Democrats poised to take back the House, Nancy Pelosi (D-California) is the favorite to be the next Speaker.

Who will be the next Speaker of the House of Representatives?

  • Nancy Pelosi (D): 66.7% chance (-200 odds)
  • Kevin McCarthy (R): 26.7% chance (+275 odds)
  • Jim Jordan (R): 13.3% chance (+650 odds)
  • Steve Scalise (R): 4.8% chance (+2000 odds)
  • James Clyburn (D): 2.0% chance (+5000 odds)
  • Field: 16.7% chance (+500 odds)

However, while Democrats are expected to win the House, Republicans are a virtual lock to retain control of the Senate.

2018 U.S. Senate Election: Majority Outcome

  • Republican Majority: 84.6% chance (-550 odds)
  • Democratic Majority: 11.1% chance (+800 odds)
  • No majority: 14.3% chance (+600 odds)

Odds to win Senate Control 2018

  • Republicans: 91.7% chance (-1100 odds)
  • Democrats: 13.3% chance (+650 odds)

At PredicIt, Republicans are at 90% to control the Senate. Smarkets lists Republicans at 76.34%.

Republicans are expected to finish with 51 to 53 total seats, according to the odds.

2018 U.S. Senate Election: Exact Republican seats after Midterms

  • 60 or more: 9.1% chance (+1000 odds)
  • 59: 4.8% chance (+2000 odds)
  • 58: 4.8% chance (+2000 odds)
  • 57: 9.1% chance (+1000 odds)
  • 56: 9.1% chance (+1000 odds)
  • 55: 12.5% chance (+700 odds)
  • 54: 15.4% chance (+550 odds)
  • 53: 16.7% chance (+500 odds)
  • 52: 16.5% chance (+500 odds)
  • 51: 18.2% chance (+450 odds)
  • 50: 13.3% chance (+650 odds)
  • 49 or fewer: 11.1% chance (+800 odds)

Piecing it all together, the betting markets expect Democrats to take the House but Republicans to retain control of the Senate.

2018 Midterm Elections: Exact Outcome

  • Democratic House/Republican Senate: 66.1% chance (-195 odds)
  • Republican House/Republican Senate: 33.3% chance (+200 odds)
  • Democratic House/Democratic Senate: 10.5% chance (+850 odds)
  • Republican House/Democratic Senate: 1% chance (+10000 odds)

This exact outcome is echoed by the famed statistician Nate Silver. His 538 team gives Democrats a 84.8% chance to win the House and Republicans an 84.5% chance to retain control of the Senate.

In the Senate, not much either. R's were always favored, and the D position became worse in late Sept./early Oct. (maybe because of Kavanaugh) and hasn't really rebounded. Over the past week, races moving in different directions and roughly cancelling out. https://t.co/EFMPjkkIqqpic.twitter.com/BTKTKpd6n8

— Nate Silver (@NateSilver538) November 4, 2018

The most likely outcome of the election is that Democrats flip the House and Republicans retain the Senate. 71.8% chance according to @FiveThirtyEight and 64% chance according to @PredictIt

— Nathan Kjer (@nathankjer) November 3, 2018


Aside from which party will win the House and Senate, bookmakers are also hanging prop bets on a plethora of key individual races across the country.

Arizona Senate Race Odds

  • Martha McSally (R): 61.1% chance (-157 odds)
  • Krysten Sinema (D): 43.9%(+129 odds)

Florida Senate Race Odds

  • Bill Nelson (D): 56.5% chance (-130 odds)
  • Rick Scott (R): 48.5%(+106 odds)

Indiana Senate Race Odds

  • Joe Donnelly (D): 57.4% chance (-135 odds)
  • Mike Braun (R): 47.4%(+111 odds)

Missouri Senate Race Odds

  • Josh Hawley (R): 59.3% chance (-146 odds)
  • Claire McCaskill (D): 45.5%(+120 odds)

Montana Senate Race Odds

  • Jon Tester (D): 74.0% chance (-284 odds)
  • Matt RosenDale (R): 31.3%(+219 odds)

Nebraska Senate Race Odds

  • Deb Fischer (R): 98.0% chance (-5000 odds)
  • Jane Raybould (D): 6.7%(+1400 odds)

Nevada Senate Race Odds

  • Jacky Rosen (D): 59.2% chance (-145 odds)
  • Dean Heller (R): 45.7%(+119 odds)

New Jersey Senate Race Odds

  • Robert Menendez (D): 84.6% chance (-550 odds)
  • Bob Hugin (R): 20.0%(+400 odds)

North Dakota Senate Race Odds

  • Kevin Cramer (R): 87.5% chance (-700 odds)
  • Heidi Heitkamp (D): 17.5%(+470 odds)

Tennessee Senate Race Odds

  • Marsha Blackburn (R): 84.6% chance (-550 odds)
  • Phil Bredesen (D): 20.0%(+400 odds)

Texas Senate Race Odds

  • Ted Cruz (R): 84.4% chance (-542 odds)
  • Beto O'Rourke (D): 20.7%(+384 odds)

West Virginia Senate Race Odds

  • Joe Manchin III (D): 80.2% chance (-404 odds)
  • Patrick Morrisey (R): 24.4%(+310 odds)

Wisconsin Senate Race Odds

  • Tammy Baldwin (D): 95.2% chance (-2000 odds)
  • Leah Vukmir (R): 10.0%(+900 odds)

Stay tuned to The Action Network for odds updates and more articles on specific races in the lead-up to the 2018 Midterms.



About the Author
Josh graduated from the University of Vermont in 2009 with a degree in English and History. He has worked at Sports Insights since 2011 as Customer Service Manager and Betting Hangout Host. He joined the Action Network in 2017.

Follow Josh Appelbaum @Josh_Insights on Twitter/X.

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