As the 2014 mid-term elections approach and record contributions pour into races from PACs, trade associations, and advocacy groups, there's been a renewed focus on the topic of "dark money" -- the funds used for issue ads and other campaign costs that come from 501(c) and 527 tax-exempt political groups. These groups aren't required to disclose their contributors, leading to concerns that corporate dollars may be influencing races in ways the electorate can't see.

In this context, the 2014 report from the Center for Political Accountability and the Zicklin Center for Business Ethics Research at the University of Pennsylvania's Wharton School of Business has drawn positive feedback while also raising a certain amount of ire within the business community. The CPA-Zicklin Index, released on Sept. 24, analyzed the voluntary political activity disclosure practices of the top 300 S&P 500 companies, rating them on 24 criteria. (These optional disclosures to PACs, trade groups, and advocacy non-profts are separate from the legally required disclosure of lobbying efforts and funding.)

There are a number of companies that embrace political transparency, such as Microsoft and top-rated Noble Energy and CSX, both of which head near-perfect Index scores. But a surprising number of companies reviewed scored a goose egg -- twenty in all, including Netflix (NFLX -0.79%) and Keurig Green Mountain (GMCR.DL). Other big brands made the bottom tier of the Index as well: Carnival Corporation (CCL 0.61%) at 18.6%, Wal-Mart (WMT -0.80%), with a score of 15.7%, and Whole Foods Market (WFM) at 10%. (The Motley Fool contacted all five of these companies to get their take on disclosure; as of the time this article was submitted, only Carnival Corporation had responded.)

Not everyone in the business community thinks voluntary disclosure is a good idea. A letter circulated after the release of the 2013 CPA-Zicklin Index by the presidents of the U.S. Chamber of Commerce, Business Roundtable, and National Association of Manufacturers asserted that the underlying agenda of the Index is to hinder or forestall business involvement in politics. The letter points out that disclosure doesn't prevent activist shareholders from submitting further proposals on the subject, and it also claims that shareholder, board, and management interest in political disclosure is exaggerated by the creators of the Index.

Politics aside, there are some practical reasons that corporations might decide not to volunteer information about their political activities, the most obvious of which is that, since the 2010 Supreme Court decision on Citizens United v. FEC, they don't really have to. Companies might take a pass on disclosure because:

The interest isn't there among shareholders
According to, run by the conservative Manhattan Institute, while activist shareholder proposals for more disclosure were the most common proxy proposal in 2013, overall shareholder support for these proposals hovered around 18%.

The company already believes it's doing enough
Especially for companies that aren't heavily invested in political issues, doing the basics may be enough to satisfy shareholders and management. Carnival Corporation chief communication officer Roger Frizzell told The Motley Fool via email, "As a company, we strive to be open and transparent in everything we do. Our political contributions are few and reported publicly by recipients as required."

Carnival isn't a big spender in the political game by corporate standards. According to the OpenSecrets database run by the Center for Responsive Politics, the company contributed less than half a million dollars this election cycle to PACs, parties, 527 groups, and candidates -- in addition to another $578,000 in lobbying on behalf of its cruise lines. It makes financial sense, in the absence of shareholder demand, to stick with the basic reporting requirements.

This appears to be the case with Keurig Green Mountain Coffee and Whole Foods Market, as well. The OpenSecrets database lists  $34,000 in political spending by Keurig this election cycle, while Whole Foods has shelled out about $48,000.

Transparency costs money, time, and effort
Unlike Carnival, Wal-Mart is what the Center for Responsive Politics describes as a "heavy hitter," a top contributor to dozens of congressional incumbents from both parties, with a political action committee that had spent $2.9 million as of Aug. 31, and contributions of $1.9 million to leadership PACs, parties, candidates, and 527 groups.

The company's CPA-Zicklin score was lowered by a lack of public disclosure of the recipients of its contributions, trade association donations, and political advertising dollars. Given Wal-Mart's reputation for relentless focus on the bottom line, though, it makes sense that the company doesn't allocate resources to disclose information that's not required of it.

They haven't gotten around to it yet
A recent analysis in The New York Times on the low Index scores of many tech companies pointed out that the industry is relatively young and transitioning from a "maverick" mind-set to understanding the need to wield political clout. The authors asserted that "to a large extent, the index represents a political maturity list," and that young tech companies suffer from a "lack of political savvy" rather than a desire to maintain secrets.

Still, Netflix, one of the companies that scored a zero on the Index, has made donations to PACs, candidates, parties, and other groups as an organization and through its political action committee this cycle, in addition to some $600,000 in lobbying expenditures. Netflix, which became a public company in 2002, has a strong interest in the rules of Internet service.  With Time Warner in the top 20 for disclosure and Comcast in the second tier, it's likely that Netflix will develop a policy eventually to voluntarily disclose more about its political activities, if only to keep up with the competition.

What do you think? Are the companies you own stock in doing enough to let the public know about how they spend their political dollars? Chime in using the comments box below.