The rally in Washington’s Ellipse that preceded the Jan. 6 riot at the U.S. Capitol was arranged and funded by a small group including a top Trump campaign fundraiser and donor facilitated by far-right show host Alex Jones.

Mr. Jones personally pledged more than $50,000 in seed money for a planned Jan. 6 event in exchange for a guaranteed “top speaking slot of his choice,” according to a funding document outlining a deal between his company and an early organizer for the event.

Mr. Jones also helped arrange for Julie Jenkins Fancelli, a prominent donor to the Trump campaign and heiress to the Publix Super Markets Inc. chain, to commit about $300,000 through a top fundraising official for former President Trump’s 2020 campaign, according to organizers. Her money paid for the lion’s share of the roughly $500,000 rally at the Ellipse where Mr. Trump spoke.