The political and policy network led by billionaire Charles Koch is backing the Republican presidential bid of Nikki Haley.

Billionaire Charles Koch’s political network is backing the Republican presidential bid of Nikki Haley, the latest sign some big donors are moving her way in a long-shot bid to block former President Donald Trump from winning the GOP nomination.

Americans for Prosperity Action, a conservative group led and partly financed by Koch, said Tuesday that it would support the former South Carolina governor and United Nations ambassador. The organization’s support is a boost to Haley as the campaign enters the final seven weeks before the first nominating contest in Iowa.