Activists seeking a November vote to ban corporate donations in the District filed suit Monday challenging a D.C. Board of Elections ruling that they did not have enough signatures, arguing a recount would prove they easily qualify for the ballot.

In a suit that raises potential questions about how petitions are validated, activists allege that the board failed to count more than 2,000 valid signatures and improperly threw out an additional 1,000 from registered voters, including tossing some that were collected from voters after they cast ballots in the April 16 primary.

“The actual number of valid signatures meet the requirements of the law and surpass the threshold of valid signatures required to place Initiative Measure #70 on the November ballot,” claims the suit, which was filed in D.C. Superior Court.

Designed to curtail business leaders’ and developers’ clout in District politics, the proposed referendum asks voters to ban corporations and limited liability companies from making donations to campaigns, legal and transition committees as well as D.C. Council constituent service funds.

But the effort, which had been expected to be approved by voters, was dealt a surprise setback two weeks ago when the board ruled that the group behind the effort fell 1,726 signatures short of qualifying for the ballot.

Under city election law, residents can petition an initiative onto the ballot by collecting signatures from 5 percent of registered voters, which currently equals 23,298 residents. Working under the name D.C. Public Trust, dozens of volunteers spent months gathering signatures in front of grocery stores, at festivals and at polling places on primary day.

Last month, they turned in about 30,000 signatures.

When the elections board conducted its review, it invalidated about 9,000 of those signatures because they allegedly belonged to unregistered voters, duplicated other valid signatures or contained missing addresses or addresses that didn’t match voter records.

But Bryan Weaver, a former council candidate who helped head up the petition effort, said that D.C. Public Trust volunteers have since recounted their submissions twice. The recount, the suit alleges, revealed at least 24,645 signatures from valid registered voters.

Weaver said the group suspects that elections officials, who appeared to use check marks to identify qualified voters, miscounted when they tallied the signatures. The suit, which requests an emergency court hearing to reverse the board’s decision, also claims that the board improperly disqualified about 1,036 signatures of registered voters.

“The work of the Board of Elections gets to the heart of our democracy,” said Weaver, a plaintiff in the suit. “What we found in our review raises serious concerns about the integrity of the democratic process in local D.C. elections.”

Ken McGhie, general counsel for the elections board, did not return calls seeking comment Monday.

Activists started pushing for the initiative this spring after several scandals, including allegations that Mayor Vincent C. Gray (D) and several council members benefited from illegal campaign contributions.

Under current law, an individual or a company cannot donate more than $2,000 to a candidate for mayor and they are limited to $8,500 in total contributions per cycle. But the activists argue that businesses can circumvent those limits by donating through various LLCs.

Several elected officials have expressed reservations about the referendum, questioning whether it would lead to more indirect campaign spending, similar to the super PACsdominating the presidential race. But most elected officials have not actively campaigned against it, acknowledging that it appears to have broad support from residents.

If it makes it onto the ballot, the initiative would not affect campaign donations by labor unions, political action committees or individuals.