Millions of dollars have been spent in support of Proposition 137, but the group opposing the ballot measure has raised and spent only a small fraction of that.

Prop 137 would create a pool of about $175 million for existing conservation and outdoors programs, including projects that aim to mitigate wildfire risk, by allowing the state government to keep more of the taxes it collects from sports equipment sales. If approved, the ballot measure would reduce Colorado Taxpayer Bill of Rights, or TABOR, refunds by between $26 and $83 for single filers, or double that for joint filers, in some years.

The ballot measure has the support of a wide coalition including various conservation groups who argue that it increases funding for existing programs that benefit Coloradans without raising taxes. But it also faces opposition, including from those who have concerns about its fiscal impacts and whether the funds support the right kind of wildfire mitigation and conservation efforts.

Proponents of Prop 137 had raised and spent more than $4 million as of the latest filing campaign finance deadline on Oct. 6, compared to just $4,700 in fundraising and $3,000 in spending by opponents, according to the Colorado Secretary of State’s Office.

Supporters of Prop 137 are registered under the name Protect Colorado’s Land and Water, Prevent Wildfires.  The filings show major financial support from conservation organizations, including more than $2 million from The Nature Conservancy, a global environmental nonprofit; a combined $900,000 from Western Resource Advocates and its action fund; $350,000 from the Fund for a Better Future; $215,000 from the Trust for Public Land; $200,000 from the Holdfast Trust associated with the company Patagonia; and $100,000 from the Conservation Fund.

The proponents also received two donations of $125,000 from Olivia and Thomas Walton, who are part of the family that owns Walmart, as well as donations of between $500 and $50,000 from other individuals, according to filings.

Supporters of Prop 137 have spent more than $3 million on consultants and professional services, including related to “signature gathering,” “campaign management” and “compliance consulting,” according to filings. Since mid-September, the proponents have also spent more than $800,000 on advertising, including digital advertising.

The opposition to Prop 137 is registered under the name Protect Colorado’s Land, Communities, and Tax Dollars. The group has received a handful of donations of between $15 and $3,500 from individual Colorado residents. The opponents have spent about $3,000, including on ads in The Gazette newspapers and on social media, yard signs, a website and consulting.