Former New York Mayor Michael Bloomberg has shown up again on Colorado campaign finance reports, with another donation to a Colorado campaign.

The latest reports from the Secretary of State’s TRACER campaign finance system, covering Sept. 13-26, show the billionaire ex-mayor gave $500,000 to Fair Maps Colorado, which advocates on behalf of two ballot measures referred by the legislature that would set up nonpartisan groups to redraw Colorado’s congressional and legislative district boundaries in hopes of preventing partisan gerrymandering.

Earlier this year, Bloomberg gave $2 million to a political action committee that backed then-Democratic gubernatorial candidate Michael Johnston, who later lost the primary to Jared Polis.

Fair Maps Colorado also took in $250,000 from Walton family heir Ben Walton in the Sept. 13-26 period.

> RELATED: Colorado campaign war chests are spilling over

In all, more than $$27.7 million flowed into campaign coffers for candidates and ballot measures in the most recent reporting period. That’s up from the $17.5 million that came in during the prior two weeks.

But political spending is up now, too.

More than $19.75 million went out the door between Sept. 13 and 26, and one independent spending committee, the Democratic-backed Coloradans for Fairness, spent a record amount on attack ads against Republicans for the five swing seats that will determine which party controls the state Senate. Currently, Republicans hold a razor-thin one-seat margin in the 35-member body.

But the biggest bucks continue to come from the oil and gas industry into efforts to defeat Proposition 112 and back Amendment 74.

Proposition 112 would set up a 2,500-foot setback between occupied structures and any new oil and gas development, up from the current 500 foot buffer round houses. Amendment 74 would allow a property owner to sue a government when regulations reduce the value of the property – a measure that could have a major impact if both 74 and 112 pass.

The top donation in the last two weeks was $2.7 million from Protecting Colorado’s Environment, Economy and Energy (also known as Protect Colorado0, which is funded by the oil and gas industry. Those dollars went to the Committee for Colorado’s Shared Heritage, which is managed by Colorado Farm Bureau and supports Amendment 74.

Protect Colorado took in $4.7 million in the same reporting period, with just under $1.4 million from oil and gas company Noble Energy and six-figure donations from nine other energy-related companies.

Protect Colorado, an independent expenditure committee, sent $5 million out the door between Sept. 13 and 26. About $1 million of that went for advertising on behalf of the Committee for Colorado’s Shared Heritage. The rest paid for the onslaught of TV and radio advertising seen in recent weeks against Proposition 112.

The next largest contribution between Sept. 13 and 26 was $2.25 million from the League of Conservation Voters of Washington, D.C. That donation went to the Conservation Colorado Victory Fund, which announced Monday it would put $3.2 million toward support for Democratic candidate Jared Polis for governor. The group spent $1.5 million of that between Sept. 13 and 26 on canvassing to back Polis.

Polis, currently a congressman from Boulder, put another $1 million from his own fortune into his campaign in the last two weeks, bringing his total to $19.775 million.

The Washington, D.C.-based progressive Sixteen-Thirty Fund, which doesn’t disclose its donors, is increasingly generous with all kinds of political campaigns in Colorado, backing Democratic candidates for the state House and Senate and a ballot measure that would limit payday loan interest and fees to 36 percent.

Between Sept. 13 and 26, the fund donated $1.5 million to two independent expenditure committees supporting Democratic candidates for the legislature. Those most recent donations bring the fund’s total in 2018 to $4 million, including $920,000 into Good Jobs Colorado, an independent spending group that backs Polis.

Good Jobs Colorado also took in $350,000 from Education Reform Now Advocacy, the money side of Democrats for Education Reform. ERNA has now given $500,000 to Good Jobs Colorado along with $350,000 in the last two weeks to the two major independent expenditure committees backing Democrats for the legislature, Our Colorado Values (House) and Coloradans for Fairness (Senate). All told, the education reform group has put $1.5 million into various political committees in 2018.

Our Colorado Values spent $658,000 in the last two weeks on attack ads against a half-dozen Republican candidates for the state House. One name that shows up more often than others on the attack ad list is Republican Toren Mushovic of Greenwood Village, who’s running against incumbent Democratic Rep. Jeff Bridges in House District 3.

But that’s dwarfed by what Coloradans for Fairness spent for ads opposing Republicans running for the five key state Senate races.

Between Sept. 13 and 26, the committee spent a two-week-record $374,257 on ads attacking Republican Sen. Tim Neville of Littleton, including $229,436 in one TV ad buy, a record for a one-time expenditure for a legislative seat. They spent $221,153 on attack ads opposing Republican Sen. Beth Martinez Humenik of Thornton in Senate District 24. Another $189.055 went for ads opposing Republican Christine Jensen for Senate District 20, in eastern Jefferson County.

In Senate District 22, which includes Lakewood, Coloradans for Fairness spent $113,737 on attack ads on Republican Tony Sanchez. And in Senate District 5 on the western slope, the committee spent $81,414 between Sept. 13 and 26 on attack ads targeting Republican Olen Lund of Paonia.

Coloradans for Fairness had its best haul of the election cycle, raising $2.1 million between Sept. 13 and 26 That includes its largest donation for 2018, $1.1 million from the Sixteen Thirty Fund. It also received $300,000 from Everytown for Gun Safety, and $235,000 from the Service Employees International Union (SEIU). The committee has now raised $3.9 million for the 2018 election.

The two big independent expenditure committees working to elect Republicans to the legislature are Colorado Citizens for Accountable Government (House and Senate) and the Senate Majority Fund.

CCAG took in $538,000 in the last two weeks and spent $322,000 of it on ads in four of the five targeted state Senate races. They spent $105,679 on ads opposing Democratic Rep. Brittany Pettersen for Senate District 22, in Jefferson County; $78,596 on ads against Speaker Pro Tem Jessie Danielson of Wheat Ridge, in Senate District 20; $72,057 to oppose Rep. Faith Winter in the Adams County Senate District 24 race; and $37,968 to oppose Democratic candidate Tammy Story in Senate District 16, also in Jefferson County. The committee also bought advertising that advocated for the Republican candidates in those races.

The committee’s biggest donation – $250,000 – came from the Washington, D.C.-based Republican State Leadership Committee*. Open Secrets reported in 2016 its contributors included Las Vegas casino owner Sheldon Adelson, the National Rifle Association, Koch Industries, Walmart and the U.S. Chamber of Commerce, its largest donor, at more than $5 million.

The Senate Majority Fund has now raised a total of $3.7 million and spent just over $486,000 between Sept. 13 and 26. They also spent on the same five Senate races in the last two weeks: $102,051 for attack ads on Winter, $98,456 for ads opposing Danielson, $75,992 for ads against Story, and $74,025 for ads opposing Pettersen. Another $12,596 was spent on attack ads against Donovan.

The Majority Fund’s biggest donors include several oil and gas companies and $200,000 from a group known as the Political Action Trust, based in Windsor, which is tied to the Dairy Farmers of America.

Correction: the Republican State Leadership Committee does disclose its donors, albeit through IRS filings the following year.