A previously published version of this article contained inaccurate information, supplied by CPA-Zicklin, about Hershey Co. That information has been corrected below.

In this age of Twitter politics and presidential company-shaming, which candidates and issues do Comcast, AmerisourceBergen, Campbell Soup, and other local companies support with money?

The answers are in the 2017 CPA-Zicklin Index, which gives a breakdown of every company in the S&P 500: what policies each company maintains on political contributions, if the company even has a policy, and links to how much money and to whom they donate. The annual CPA-Zicklin Index includes many local names we recognize: FMC Corp., Lincoln Financial, PNC Financial, and Hershey Co.

The index, started in 2009, shows the largest public U.S. companies' political activity in a high-spending era marked by an unprecedented flood of "dark money," said Bruce Freed, president of the Center for Political Accountability in Washington, which partnered with the Wharton School of the University of Pennsylvania to create the index. Wharton held a special round-table event on Friday to release the latest results.

For investors, the index is a useful tool to evaluate companies' policies and accountability. For companies, it helps "assess whether they follow best practices for disclosure and accountability, and the extent to which they commit," Freed added. Anyone can access the index via the center's website, PoliticalAccountability.net. For dollar amounts, the CPA-Zicklin Index links to databases such as the Federal Election Commission's fec.gov, OpenSecrets.org, and FollowTheMoney.org, and its own new database, TrackYourCompany.org.

Philly's hometown communications giant, Comcast Corp., for instance, scored fairly high, with 82.9 points out of 100 on the index. Comcast wins points for transparency because it has a stated policy on political contributions disclosed on its corporate website and posts a 45-page document listing individual donations in the most recent 2016, 2015 and 2014 election cycles.

"Political contributions are made from employee-funded political action committees ('PACs') that are sponsored by Comcast. The Comcast PACs are operated by a board of directors, chaired by the senior executive vice president. When permitted by law, political contributions are also made out of corporate funds," the company says.

Comcast's largest 2016 donations included $250,000 to "Yes on the Los Angeles County Traffic Improvement Plan" in California; $367,804 to the Republican Party of Florida; and $450,000 to "Defeat the Tax on Oregon Sales." Search its investors site (www.cmcsa.com) for the "Comcast Corp. Statement on Political and Trade Association Activity."

In Pennsylvania, Comcast donated mostly to individual candidates, including $50,000 to Tom Wolf for governor, $12,500 to the Senate Republican Campaign Committee, $21,000 to the Mike Turzai Leadership Fund, $16,000 to Friends of Jake Corman, and $20,600 to Friends of Joe Scarnati. Turzai, Corman and Scarnati are Republican leaders in the Assembly.

With the highest score in the 2017 CAP-Zicklin index was Becton Dickinson, at 100 points. Edison International, Edwards Lifesciences, HP Inc., Noble Energy, PG&E, Sempra Energy, and State Street Corp. all tied for second place with 97.1 points out of 100.

Among companies in the Philadelphia region, AmerisourceBergen scored 85.7, and Campbell Soup 68.6.

Hershey scored 64.1, the same as last year. (A previous version of this article indicated Hershey had scored zero. CPA-Zicklin, which released online results on Tuesday, said a glitch in its system prevented the correct score from being published).

Those with lower scores included FMC Corp. (31.4); Lincoln National (37.1), which improved from last year; and PNC Financial Services (5.7).

The average total score in the 2017 index was 43.1 points.

Shareholder engagement helped raise scores, Freed explained, especially now that large passive index investors such as Vanguard and BlackRock are speaking out more on issues important to stockholders.

"Companies engaged by shareholders, and reaching an agreement, had significantly better disclosure and accountability policies," he said. "For all three years that we have evaluated the S&P 500, there's been a strong positive correlation between shareholder engagement and the company's index score."

As President Trump brings upheaval to the business landscape, calling out individual companies he either favors or criticizes, "companies already favoring transparency have not gone underground to conceal their political spending," Freed added.

How did the CPA-Zicklin Index come into being?

Lawrence Zicklin, a former partner at the Wall Street firm Neuberger Berman, funded the Zicklin Center for Business Ethics Research at the Wharton School. (He currently teaches ethics at Wharton and NYU's Stern School of Business.)

William Laufer, director of the Zicklin Center, first proposed the index in July 2009.

Zicklin initially grew interested in campaign finance a decade ago, when Massey Energy CEO Don Blankenship donated $3 million to a West Virginia judge who later decided a case in the company's favor. Blankenship finished a prison sentence this year related to a Massey mining accident.

"I've also heard from many companies that they would like to get out of this game if they could," Zicklin said. "In some cases, companies are being extorted. They're told there's a bill they really ought to support by some nameless politician, and they have to" donate money.