AUGUSTA – Opponents of a property tax cap referendum have spent more than twice as much as referendum supporters through Oct. 21, according to campaign finance reports filed Wednesday.

The reports, filed with the Commission on Governmental Ethics and Election Practices, showed that the two political action committees opposed to the cap had spent nearly $1.2 million between them. The three political action committees that support the referendum had spent a little more than $500,000.

That helps explain why television ads urging Mainers to vote against the tax cap have far outnumbered those advocating a yes vote.

Opponents spent more than $429,000 on advertising from Oct. 1 through Oct. 21 alone, plus an additional $20,000 through Tuesday, the documents said. Opponents of the cap began running television ads Sept. 22 and have run five ads so far, said Larry Benoit, a leader of the opposition campaign.

Cap supporters reported $69,000 in advertising expenses from Oct. 1 through Oct. 21 and no major expenditures since then. Supporters of the cap did not begin TV advertising until Oct. 20 and have run only one ad so far, said Jen Webber, a spokeswoman for Tax Cap Yes!

Mainers will vote Nov. 2 on the referendum, which would cap property taxes at 1 percent of a property’s value. Supporters say people are being taxed out of their homes, but opponents say the cap would wreak havoc on municipalities and schools.

The latest finance reports show that supporters continue to get much of their money from relatively small contributors. Opponents are turning to large gifts from corporations and interest groups to finance much of their campaign.

Pro-cap contributions came from citizens who represent “the heart and soul of Maine” while opponents relied on business and government money to fill their coffers with large donations, said Phil Harriman of Tax Cap Yes!

Dennis Bailey of Citizens United said businesses oppose the cap, even though it would cut their property taxes, because they see it as destructive. He said interest groups representing municipalities and teachers oppose it because they believe it will harm a wide range of government services, including schools and libraries.

From Oct. 1 through Oct. 21, Citizens United reported 13 cash contributions of $5,000 or more, including $111,200 from the Maine Municipal Association, $50,000 from the Maine Education Association and $25,000 from L.L. Bean.

Other big contributions to the opposition camp included $25,000 from moveon.org in California, an activist group; $15,000 from Fairchild Semiconductor of South Portland; and $10,000 each from the Maine Association of Police, Verizon, the Dead River Co. and Richard Bresnahan of Hope.

The biggest contributors to Tax Cap Yes! for the same period included Harriman, a co-founder of Tax Cap Yes!, who gave $10,000. Kenneth Cianchette, the father of Tax Cap Yes! co-founder Eric Cianchette, contributed $5,000.