Mark Holden, general counsel of Koch Industries, left, with his boss, Charles Koch, in Koch's office in Wichita in 2015. (Nikki Kahn/The Washington Post)

Billionaire Charles Koch is consolidating the array of conservative advocacy groups financed by his donor network, merging all the organizations into the main political arm, Americans for Prosperity, officials announced Friday.

Network leaders cast the surprising move as a way to operate more efficiently and better coordinate their organizing reach on the ground, which has increasingly become the focus of the operation. The change means that three smaller groups that target Latinos, veterans and millennials will now operate as part of AFP. The leaders of the LIBRE Initiative, Concerned Veterans for America and Generation Opportunity are all expected to remain in place, but will be running their organizations as branded projects under the AFP banner.

"For us, the way to be most effective, particularly this election cycle, heading into final weeks, and most importantly into 2017 and beyond, is with our grass-roots operation," Mark Holden, chairman of the board of Freedom Partners, the network's funding arm, said in an interview. "What we’ve done in combining them under AFP is going to make us much stronger."

Holden said he did not anticipate layoffs as part of the changed structure, which he said would allow the groups to better target different constituencies and avoid duplicating efforts. The changed structure, which will not be finalized until later this year or early next year, will mean that each of the groups will have a presence in AFP's 35 chapter states. Luke Hilgemann, AFP's chief executive, will oversee the expanded organization.

"We want to grow this into a movement of millions," said Holden, who is general counsel of Koch Industries. "We’re hopeful to grow more."

The change comes days after the Koch network announced it was shifting its focus from television ads to its field program in the final month of the 2016 elections. As of now, the network does not plan to air any commercials after Oct. 4.

Holden said that the moves are not driven by a cash crunch, even though some donors have balked at the network's decision to stay out of the presidential contest.

"The fact that we haven’t been in the presidential has led people who want to play in the presidential to not work with us on that, but we’ve been able to meet all our goals," he said. "I think we’re in a good place."

The network's financing of various advocacy groups began when the operation was far more low-profile, seeking to shield the role the Kochs and other donors played in its financing. In early 2014, when The Washington Post and Center for Responsive Politics used tax filings to map out the maze of groups financed by the network, officials declined to confirm how the organizations were connected. But in the years since, the network has taken a more public posture, inviting reporters to attend its twice-a-year donor seminars.