VanderSloot says he plans to host fundraisers and bundle contributions for Rubio's campaign, as well as give to a super PAC supporting him. He didn't say how large a total investment he planned to make.
The Idaho Republican said he has given to other Republican presidential hopefuls this election cycle, including Scott Walker and Carly Fiorina. He said Fiorina was his second choice.
Jeb Bush, another candidate VanderSloot considered backing, "was losing steam, and the air's out of his balloon," he said.
Rubio is currently on a West Coast fundraising swing. Last month he landed the backing of billionaire donor Paul Singer.