The next US presidential election is a smidge less than three years away, yet just about everyone is wondering who the Democrats could rally behind to challenge Donald Trump in 2020. So far, senator Bernie Sanders is in the lead, according to PredictIt, a political prediction stock market.

Candidates begin laying the groundwork for a presidential run years in advance—the beginning of the next campaign seemingly begins when the last one ends. And Trump, an unconventional Republican whose time in office has been beset by turmoil (paywall), has inspired a sense of urgency among those who oppose him. Even so, no clear leader for the Democratic party has emerged since the end of Barack Obama’s second term and Hillary Clinton’s defeat in 2016.

Rank Name Price (cents) 1 Bernie Sanders 21 2 Kamala Harris 17 3 Elizabeth Warren 15 4 Kirsten Gillibrand 14 5 Joe Biden 13 6 Cory Booker 11 7 Amy Klobuchar 8 8 Andrew Cuomo 7 9 Mark Zuckerberg 4 10 Tim Kaine 2 Source: PredictIt Dec. 29, 2017

PredictIt translates prediction market data into US cents, with the highest price signalling the most likely outcome at a particular time. Sanders, who challenged Clinton for the nomination in 2016, is seen as the likely nominee at 21 cents a share. California senator Kamala Harris is next at 17 cents, followed by Massachusetts senator Elizabeth Warren at 15 cents.

Three of the top-five potential candidates are women —New York senator Kirsten Gillibrand comes in fourth at 14 cents, just ahead of former vice president Joe Biden at 13 cents.

At the bottom of the top-10 are Facebook founder Mark Zuckerberg and Tim Kaine, the Virginia senator who was Clinton’s running mate, at 4 cents and 2 cents, respectively.