It’s still nearly a year until the Iowa caucuses begin, traditionally the start of the presidential primary campaign in the US, but Ladbrokes is already offering a market on the winner (in terms of overall state delegates). The favourite is Kamala Harris at 5/1, followed by Elizabeth Warren at 10/1, Cory Booker at 20/1 and Kirsten Gillibrand (pictured) at 25/1. I’d steer clear for now, however, as potential candidates such as Joseph Biden aren’t currently listed.
I’d also steer clear of the vice-presidential nominee market at the moment. Vice-presidential nominations depend heavily on the nominee, and can either be candidates who performed strongly in the primary (such as John Edwards in 2004), respected grandees (Dick Cheney in 2000 and Joe Biden in 2008), or candidates intended to provide geographical or political balance to the ticket (Michael Pence and Tim Kaine, both in 2016). Occasionally, nominees can be completely unexpected (Sarah Palin in 2008).
As an alternative I’d suggest betting on the party of the winner. At the moment Betfair is offering 1.7 (58.8%) on the Democrats winning, and 2.4 (41.7%) on the Republicans. You can also get 50 (2%) on an independent candidate. Given that Donald Trump’s opinion ratings are barely above 40%, with a majority of voters strongly disapproving of him, I can’t imagine a scenario where he manages to win. I’d suggest you bet against the Republicans at 2.5 (40%), which is equivalent to betting on a Democratic or independent victory at 1.67 (60%).