Audit committees took it up another notch in the past year in terms of the types and amount of information they voluntarily provide to investors, according to the latest analysis.

A joint report issued by the Center for Audit Quality and Audit Analytics says audit committees made incremental increases in their proxy disclosures from 2016 to 2017 addressing a number of different issues. The analysis of S&P 1500 companies also shows audit committees at larger companies tend to be more likely to provide voluntary disclosures than those at smaller companies.

The analysis didn’t find increases across all topics, however. Fewer audit committees, for example, address issues involving audit fees compared with most other topics, and this year’s annual analysis showed no growth from the prior year on that particular subject.

As an example of a straightforward disclosure, the largest audit committees had a little more to say each year since 2014 on the issues they considered in selecting or appointing the audit firm. Only 13 percent of the largest S&P companies addressed the topic in 2014, and that’s grown to 37 percent in 2017. Among mid-cap companies, however, 10 percent disclosed it in 2014, growing to 24 percent in 2017. And among small-cap companies, only 8 percent made such disclosures in 2014, rising to only 17 percent by 2017.

Trends are similar when it comes to issues like the criteria audit committees considered when evaluating the audit firm and the disclosure that evaluating the audit firm is an annual event. There’s more disparity, however, between the largest companies compared to mid-cap and small-cap companies when it comes to stating that the audit committee is involved in selecting the audit partner and that the audit partner rotates every five years.

Audit committees are a little more guarded, however, when it comes to discussing audit fees, unless there’s a big change they want to explain. For example, 20 percent of audit committees at S&P 500 companies said it was their duty to negotiate audit fees, up from only 8 percent in 2014. Yet only 4 percent of mid-cap companies and small-cap companies said as much in 2017.

When there’s a change in audit fee to explain, 31 percent of the largest companies provided disclosure, down slightly from 34 percent in 2016. Mid-cap companies held flat in that area at 32 percent, while 35 percent of small-cap companies addressed that issue.

Audit committees are under no explicit obligation to disclose many of those issues, but they’ve faced some demand from regulators and investor advocates to provide more voluntary disclosure as a way of demonstrating their oversight of external auditors. The Securities and Exchange Commission issued an extensive concept release in 2015 pondering a number of ways audit committees could be required to enhance their proxy disclosures but has not acted further on any kind of formal requirement.