In an interview with Kai Ryssdal of American Public Media's"Marketplace," Koch said that lower projection reflected smaller-than-expected contributions.
"Our latest budget is going to be lower because people aren't contributing as much," he told Ryssdal. "Probably the total budget over the two years I would guess would be 750 [million], and the amount in politics is 250 [million]."
The Koch-backed political network has emerged over the last decade as one of the most influential power centers in American politics. Koch's comments are the first indication that the organization is not meeting its fundraising projections for 2016. A gathering of more than 450 network donors in August in California drew a record number of attendees, including 146 first-timers, officials said at the time.
Earlier this year, Koch said that the network -- which is overseen by the nonprofit business chamber Freedom Partners -- would spend roughly $300 million on political activity through a super PAC and various advocacy groups.
James Davis, a spokesman for Freedom Partners, said Wednesday, "We're on pace to meet our fundraising goals."
Koch noted in the Marketplace interview that the majority of the money spent on electoral activity would not come from him or his brother David.
A "very small portion of that 250 [million] comes from the so-called Koch Brothers, and even less from me than from my brother because everybody can choose what they want to give to," he said. "So it isn't the Koch brothers doing it. It's other people doing it."
The bulk of the money being raised through Freedom Partners finances a host of nonprofits, think tanks and higher education programs.