In the face of mounting pressure, many major U.S. companies are still listening to their shareholders and are disclosing their political spending, according to the eighth annual CPA-Zicklin Index of Corporate Political Disclosure and Accountability.

This year the number of Standard & Poor's 500 companies receiving scores of 90 percent or above for political disclosure and accountability edged up to 57. That's seven more than last year's 50 companies, and more than double the 28 firms in 2015, the report said.

Also significant, the study said, is that the average overall index score for the 414 companies that have remained part of the S&P for three years (called “core companies” in the report) has continued steadily rising, from 41.6 in 2015 to 49.7 in 2018. The higher score correlates with more disclosure.