The business community is lining up behind mayoral challenger state Sen. Ed Murray (D-43, Capitol Hill).

Exhibit A: People for Ed Murray, a pro-Murray political action committee (PAC), has been largely funded by the Civic Alliance for a Sound Economy (CASE), the political arm of the Seattle chamber of commerce, which endorsed Murray in June. CASE has given $52,500 of the group's total of $125,000.

As we've reported before: other business interests that have contributed to the pro-Murray PAC include the Washington Beverage Association and the commercial real estate lobby (the National Association of Industrial and Office Properties), $5,000 and $10,000 respectively.The "establishment" charge against Murray certainly holds up when it comes to some of CASE's other big contributors, several of whom have an ax to grind with Mayor Mike McGinn. 

But what businesses are behind the generous $52,500 in CASE money (a hefty 42 percent of the PAC's dollars)?

The biggest contributor to CASE is actually Vulcan, the South Lake Union developer that incumbent Mayor Mike McGinn has  championed. They've given $22,500 to CASE ($17,500 directly and $5,000 through a subsidiary, City Investors LLC).

While the Vulcan contributions seem to confirm the "establishment" charge that McGinn has leveled at Murray, it actually complicates McGinn's messaging. Not only did McGinn advocate for South Lake Union upzones and alley vacations, but Vulcan largely financed Great City, the urbanist, pro-density group McGinn founded before he ran for mayor. And in this year's race, Vulcan employees have contributed generously to McGinn's campaign, giving $3,650 to the mayor. (They've given $3,500 to Murray, including a $700 contribution from the company itself.)

Mixed messages about Vulcan money aside, the "establishment" charge against Murray certainly holds up when it comes to some of CASE's other big contributors, several of whom have an ax to grind with the mayor.

They include:

• The R.C. Hedreen Company—a downtown developer that has refused to promise union leaders with Unite HERE Local 8, the hospitality workers' union, that its proposed downtown convention center hotel will be a unionized operation—which gave $10,000. (Unite HERE is funding its own PAC to support McGinn.) The Hedreen compnay has also given $500 directly to the Murray PAC and $2,800 to Murray's campaign itself when you include contributions from individuals and the company.

• Comcast ($5,000), a competitor to McGinn's favored high-speed Internet provider, Gigabit Squared. Last year, McGinn announced a deal to lease unused "dark fiber" to the company, which will provide Internet service at speeds up to 100 times faster than conventional broadband. 

• The Seattle Mariners ($5,000), which opposed the proposed half-billion-dollar NBA arena in SoDo on the grounds that it would create untenable parking, scheduling, and traffic problems in the vicinity of SafeCo field, where the Mariners play. 

• Engineering and construction firm Parsons Brinckerhoff ($5,000), the primary firm responsible for designing and building the downtown tunnel. McGinn made the tunnel his cause célèbre both during his 2009 campaign and in 2011, when he fought (and raised money) for the anti-tunnel campaign (ultimately, voters expressed their support for the tunnel by saying "yes" to the nonbinding resolution). 

A couple of minor caveats: Republic Services, a Teamsters-affiliated recycling company that serves parts of Seattle, also gave to CASE—an expression of support from the kind of lefty union whose support typically (or stereotypically) goes to McGinn.

And the environmental group Climate Solutions gave $1,000 to CASE. Climate Solutions Policy Director KC Golden testified against the coal train proposal with McGinn in June. Finally, one of the other top contributors to CASE, philanthropist Maryanne Tagney-Jones (who gave CASE $5,000) also maxed out to McGinn. 

UPDATE: Climate Solutions spokeswoman Kimberly Larson says the contribution listed on state Public Disclosure Commission documents as coming from Climate Solutions actually came from Climate Solutions board member Stephanie Solien and was incorrectly filed by CASE as coming from Climate Solutions itself; we have a call out to CASE VP George Allen.)

Chamber senior VP George Allen says CASE contributors "generally understand where the money is going"—in this case, to Murray.

There are two PACs supporting McGinn as well, but we cannot take a similar peek behind the curtain as we did with People for Ed Murray's CASE contibutors. CASE is itself a PAC and so must disclose who its individual contributors are.

However, the McGinn PACs—Unite Here TIP State and Local Fund and Working Families for McGinn— are (so far) being solely funded by unions: the hotel and resturant union, UNITE HERE ($51,000); the United Food and Commercial Workers Local 21 ($15,000); the Washington Machinists Council ($2,000); and the Public Serivce and Industrial Employees ($1,000). Unions don't meet the defition of PACs themeselves (their primary purpose is not electoral), and so their contributions, from their general fund, don't legally require more discolusre.