The gun-control group responsible for a 2018 march on Washington, D.C., raised the vast majority of its funds from undisclosed donations over six figures, a recently released tax document shows.

The March For Our Lives Action Fund, a 501(c)(4) "social welfare" organization launched in the aftermath of the deadly 2018 shootings at Florida's Marjory Stoneman Douglas High School, is bankrolled almost entirely by large donations in excess of $100,000. The group reported $17,879,150 in contributions and grants over the course of 2018, its first year of operations. Ninety-five percent of those contributions came from 36 donations between $100,000 and $3,504,717—a grand total of $16,922,331.

The group's reliance on a small number of large donations raises questions about its ability to turn rally-goers and supporters into donors. It also provides ammunition to gun-rights activists who have long cast the gun-control movement as driven not by grassroots supporters, but by billionaire benefactors like Michael Bloomberg.

The group's 990 tax form shows another 38 donations totaling between $5,000 and $100,000, which together accounted for an additional $876,114 of revenue. The remainder, just 0.5 percent of total receipts, came from those giving less than $5,000.

While March For Our Lives is not required to disclose its donors under federal law, some businessmen and Hollywood celebrities vowed to provide generous contributions for the group's 2018 march on Washington, D.C. Salesforce CEO Marc Benioff and billionaire businessman Eli Broad both gave $1,000,000, two of six donors to do so. George Clooney and wife Amal Clooney gave $500,000, as did fashion company Gucci.

The group's spending went primarily toward its March 24, 2018, march on Washington, D.C., which garnered several hundred thousand attendees and featured speakers pushing for new gun bans and magazine limits. The event cemented March For Our Lives as one of the most prominent and radical gun-control groups in the country. The group has since called for confiscating up to 117 million firearms from Americans as part of its highly publicized "A Peace Plan for a Safer America."

The final cost for the group's 2018 march was $7.8 million. $4.7 million appears to have gone to Harbinger LLC, a D.C.-based marketing agency, for production services. The group later embarked on a 24-state, 60-day, $4 million summer tour to educate and register young voters.

An additional $3.8 million was put toward gun-control advocacy efforts, which were "instrumental in ensuring the passage of over 50 pieces of gun violence legislation, at the state and federal level," the forms claim.

Travel grants were also cut by the nonprofit to roughly 20 organizations, including the Center for American Progress, National Urban League, InspireNOLA Charter Schools, and the PICO National Network. The PICO National Network, which has since changed its name to Faith in Action, has worked in conjunction with liberal groups like the Center for Popular Democracy to quietly target Republican politicians up for election.

Millions more were spent on independent contractors. Soze Productions Inc., a New York-based group, was paid $1.6 million for tours and production services. Michael Skolnik—liberal activist and founding partner of the Soze Agency, which works with numerous left-wing political organizations—is listed as the CEO of Soze Productions by New York state business records.

Other groups receiving money included Hand in Hand Inc., a Los Angeles-based company with practically no online presence, which was paid $1.25 million for production services. California business records show the group was launched in June 2018 and is led by Hollywood producer Evan Prager. Law firm Loeb & Loeb LLP was paid $932,000 for legal services; the group finished 2018 with $2.4 million in assets. K2 Intelligence LLC, a New York-based investigative and cyber defense company, was paid $2.1 million for security services.

March For Our Lives did not immediately respond to a request for comment on this story.