Merck, Qualcomm and United Parcel Service topped the rankings in the CPA-Zicklin Index of Corporate Political Accountability and Disclosure, released Wednesday.
The three companies all scored 94.3 on a scale of 100 as the highest level of disclosure and accountability.
AFLAC, CSX and Microsoft — all scoring 92.9 — ranked second highest.
They were followed by Noble Energy and Gilead Sciences, each scoring 91.4; Conoco Phillips, Exelon, J.P. Morgan Chase, Time Warner and Wells Fargo, each scoring 90; and Intel, PG&E, and Yum! Brands, each scoring 88.6.
The 16 companies sharing the top five scores set a new “high standard for overall political disclosure and accountability,” according to a statement about the rankings. “In 2012, six companies were identified as top corporate leaders.”
The index rated the top 200 companies in the S&P 500 index.
“A strong cross-section of the top tier of American business has established political disclosure as a corporate mainstream practice, and we're very encouraged to see this strong trend gaining momentum,” Bruce Freed, CPA president, said in the statement.
The CPA is a non-profit, non-partisan organization focused on bringing “transparency and accountability to corporate political spending,” addressing a risk to shareholder value, according to the statement.
The Carol and Lawrence Zicklin Center for Business Ethics Research is at The Wharton School of the University of Pennsylvania.