(Bloomberg) -- The Charles Koch-backed Americans for Prosperity Action will cut off funding for Nikki Haley’s presidential campaign, a blow to the sole remaining Donald Trump challenger.

AFP, a conservative super political action committee, has spent millions of dollars since the fall on advertising and voter outreach efforts for Haley helping to fuel her bid for the Republican nomination. 

“Given the challenges in the primary states ahead, we don’t believe any outside group can make a material difference to widen her path to victory,” Emily Seidel, a senior advisor for AFP Action, said in a memo Sunday, obtained by Bloomberg News. “And so while we will continue to endorse her, we will focus our resources where we can make the difference. And that’s the US Senate and House.”

Politico earlier reported the group’s decision.

The move to cut funding for Haley’s presidential effort comes a day after she suffered a roughly 20-percentage point loss to Trump in South Carolina, the state where she served two gubernatorial terms, before serving as Trump’s UN Ambassador. Haley vowed to stay in the race until Super Tuesday on March 5, when more than a dozen states vote. But she has virtually no path to secure the nomination with Trump expected to clinch enough delegates by mid-March. 

Since endorsing her in late November, Americans for Prosperity Action has spent more than $32 million in support of Haley, Federal Election Commission records show, with the bulk of that amount going to digital advertising and canvassing.

“AFP is a great organization and ally in the fight for freedom and conservative government. We thank them for their tremendous help in this race,” Haley’s campaign spokesperson, Olivia Perez-Cubas, said in a statement late Sunday. “Our fight continues, and with more than $1 million coming in from grassroots conservatives in just the last 24 hours, we have plenty of fuel to keep going. We have a country to save.”

(Updates with statement from Haley’s campaign spokesperson in last paragraph)

©2024 Bloomberg L.P.