For the purposes of this market, a "major candidate" is defined as any candidate who, at any point during the race, had a polling average of at least 10%. In previous years, according to realclearpolling.com, the candidates who would have met this criteria were:

2024: Donald Trump, Ron DeSantis, Nikki Haley

2020: Donald Trump

2016: Donald Trump, Ted Cruz, Ben Carson, John Kasich, Marco Rubio, Jeb Bush, Scott Walker, Carly Fiorina, Rand Paul

2012: Mitt Romney, Newt Gingrich, Rick Santorum, Rick Perry, Herman Cain, Ron Paul, Michele Bachmann

2008: John McCain, Rudy Giuliani, Mike Huckabee, Fred Thompson, Mitt Romney

• Update 2025-11-14 (PST) (AI summary of creator comment): A candidate must actually be running for their polling average to count toward the 10% threshold. Candidates who never enter the race will not be considered major candidates, regardless of their polling numbers.