Backers of efforts to write a ban on same-sex marriage into the state's constitution are saying little about their largest contributor.

Marriage Education Initiatives, a Salt Lake nonprofit corporation, formed on Oct. 18, according to state records — the same day it gave a $50,000 in-kind contribution to Utahns for a Better Tomorrow. The following day, it gave a $120,000 cash contribution to the UBT campaign for Amendment 3, which will be on the Nov. 2 ballot.

UBT spokeswoman Nancy Pomeroy said she had no information about Marriage Education Initiatives beyond its Salt Lake address listed on Tuesday's finance report.

There are four businesses at the address Marriage Education Initiatives listed on state documents, and Marriage Education Initiatives is not one of them.

The corporation's trustees are Richard Jaussi, Neal Blair and Lloyd Davis, according to the state Division of Corporations. Jaussi is an independent contractor for Parents for Choice in Education, which supports tuition tax credits and vouchers.

None of the three trustees could be reached for comment Wednesday.

Roger Tew, an attorney in the suite opposite the one listed in state finance reports, said he had sublet space to Blair and Chuck Warren, but both had left by Oct. 1. Warren said he had no knowledge of Marriage Education Initiatives but said he is vice president of Bully Pulpit Inc., which gave a $52 in-kind contribution to UBT.

Sandy Peck, executive director of the League of Women Voters of Utah, said it's strange that so little is known of such a large donor.

"I think it's really hard for voters to know how to vote when they don't know what the source of the funds are," she said. "It's just really imperative you have disclosure."

Marriage Education Initiatives and other donors have given a combined $447,500 so far to UBT and the two other campaigns backing Amendment 3 — the Constitutional Defense of Marriage Alliance and Yes! For Marriage.

Only a few of those contributions have come in from individual out-of-state donors, and none has come from national family values groups.

Out-of-state interest groups, meanwhile, have contributed to the $704,400 the Don't Amend Alliance has raised to fight the amendment. The National Gay and Lesbian Task Force, National Center for Lesbian Rights and the Human Rights Campaign have given a combined $65,000 to Don't Amend.

Supporters have a combined $43,400 on hand in the final week before the election. Don't Amend has $101,846.