Unlike most incumbents, President Trump is almost certain to face one or more challengers for his party's nomination in 2020, if he seeks re-election.

But the president need not worry about any threat to his nomination from outside the White House, according to the prediction market Predictit.

The site, where "traders" buy and sell shares in the outcomes of future events, opened trading on the 2020 Republican presidential nomination Wednesday. And the share prices for Trump easily outpriced those of all his potential Republican challengers.

Here is the full list of candidates and their share prices as of Wednesday night:

Donald Trump - 46 cents
Mike Pence - 21 cents
John Kasch - 7 cents
Marco Rubio - 6 cents
Nikki Haley - 5 cents
Ted Cruz - 5 cents
Ben Sasse - 4 cents
Paul Ryan - 4 cents
Tom Cotton - 3 cents
Rand Paul - 3 cents

It is notable that the leading challenger to the president comes not only from within his own administration, but from off his own 2016 ticket. Share prices for Vice President Pence opened 300% higher than those for the third-place candidate, Ohio Gov. John Kasich.

Needless to say, there is a long way to go and we can expect some major swings in this market before the real campaigning begins in a couple of years.