The Kamala Harris campaign sent a signal to deep-pocketed donors Monday by blessing the work of 13 independent groups that could help elect the vice president over the final 50 days through advertising, registration or other voter mobilization efforts.

The announcement comes as the Harris campaign remains flush with late-summer cash after raising $615 million in the first six weeks after taking over President Joe Biden’s campaign.

But the ecosystem of supportive nonprofits and super PACs that were set up to support her campaign are in many cases still recovering from a tumultuous summer that disrupted fundraising, particularly among wealthy donors who can write large checks.

Harris campaign chair Jen O’Malley Dillon said in a statement Monday that the 13 groups, including several that do not disclose their donors, were important for the vice president’s campaign.

“These groups’ efforts to register voters and mobilize our broad and diverse coalition will play a critical role in winning this November,” she said.

The list includes operations that the Biden campaign previously embraced, including the principal advertising super PAC, Future Forward, along with American Bridge 21st Century, which is advertising in Wisconsin, Michigan and Pennsylvania, and Priorities USA, which has been doing digital spots to support the Democratic ticket.

The list also included six groups that focus on persuading and turning out specific constituencies that Harris has identified as crucial for November, including several that have partnered with Future Forward on advertising campaigns.

They include BlackPAC, which targets African American voters; Somos Votantes, which targets Latinos; AAPI Victory, which targets Asian voters; Galvanize, which targets White women in battleground states; Won’t PAC Down, which focuses on Millennial and Generation X voters; and Emily’s List, a group focused on electing Democratic women that has been advertising on abortion rights this year.

Other favored groups include Clear Choice, a recently formed super-PAC focused on discouraging potential Harris voters from voting third party, and the Democratic Data Exchange, or DDX, a company that allows for voter information to be exchanged between independent groups on the left and Democratic campaigns like Harris.

Two major liberal donor networks round out the list: America Votes, a hub for coordinating field efforts in battleground states, and Strategic Victory Fund, a spinoff of the Democracy Alliance that focuses on elevating liberal voices in battleground states.

Federal candidates like Harris and their advisers are allowed to encourage independent groups that can collect checks of unlimited value, even if those groups later spend that money to help their campaigns. But candidates and their agents are not allowed to direct spending by the groups or specifically ask for large contributions from donors.

In practice, that means campaign surrogates or candidates will appear at events for groups they support without making a specific donation requests. Since Harris took over the Biden campaign, one of her campaign co-chairs, former New Orleans mayor Mitch Landrieu, appeared at an event for American Bridge. Doug Emhoff, the vice president’s husband, is scheduled to attend a separate American Bridge event in the coming days.

The Harris campaign is expected to deploy more surrogates in the coming weeks to help the chosen 13 groups raise money, even as they continue to warn donors that the campaign needs more funding despite raising nearly three times as much as Republican candidate Donald Trump in August.

O’Malley Dillon sent a Sept. 7 memo to major donors called “A Fierce Spending Battle This Fall” that highlighted the deep pockets of independent groups supporting Trump.

“We’re running against an entire army of MAGA-aligned super PACs and outside groups,” O’Malley Dillon said in the memo. “Already, new, billionaire-funded soft money groups are springing up at a rapid pace, trying to make up for his lack of grassroots support by raising hundreds of millions from high-dollar donors — and they are using it to attack Vice President Harris.”

Trump has publicly praised some of the groups supporting him in social media posts, showering public praise on major donors like Tesla chief executive Elon Musk, who is funding a field operation to help Trump’s campaign.

“Preserve America has been doing a great job with ads and all other efforts on behalf of MAGA,” Musk wrote on Truth Social earlier this month, before naming out the group’s primary donor, the heir to a casino fortune. “Thank you Miriam Adelson!”