Billionaire Donald Trump has new company at the top of the latest Iowa presidential poll.

FOX News Radio's Jared Halpern has more from Washington:

Dr. Ben Carson has tied Donald Trump in a Monmouth University poll of likely Iowa Republican caucus-goers... both picking up 23% for the top spot.

Carly Fiorina, another candidate with little political experience, is the only other Republican with double digits at 10%. She's followed by Texas Senator Ted Cruz, Wisconsin Governor Scott Walker and former Florida Governor Jeb Bush.

Carson, however, has the strongest favorability rating -- 81%, just 6% see him unfavorably. Trump's favorability rating is up to 52% in this poll.

In Washington, Jared Halpern, FOX News Radio.