U.S.-traded companies may be under greater pressure to disclose their exposure to the potential cost of climate policies under a new U.S. Securities Exchange Commission staff guidance issued Tuesday.

In the Staff Legal Guidance, the Division of Corporation Finance said it's changing how it analyzes companies' "no-action" requests on shareholder proposals relating to environmental, financial or health risks.

The guidance reverses the staff's previous position, which has so far prevented shareholders from asking companies about their balance sheet exposure to climate change, greenhouse gas emission policies and other issues. Now, for example, insurance companies may be requested to disclose the economic costs of climate change to its customers; coal companies to reveal the potential impact of a climate bill on their production; and utilities would have to show how their generation portfolios may have to be restructured to meet greenhouse gas emission targets.

Mindy Lubber, head of Ceres, a network of investors and environmental organizations, said the SEC staff guidance "overturns antiquated, nonsensical rules, keeping with the times and protecting investors." Ceres directs the Investor Network on Climate Risk, whose member public pension funds, institutional investors and fund mangers represent around $8 trillion in assets.

Lubber said the old position meant the SEC either threw out valid, important and compelling resolutions that were about protecting investors, "or it forced investors to do mental calisthenics to re-write shareholder resolutions."

Companies could previously ask the SEC for a no-action letter is shareholder requests focused on disclosure of "risk." If the SEC grants a no-action request, companies don't have to respond to shareholder resolutions.

As Congress and the Obama administration move toward federal regulation of greenhouse gas emissions, major segments of the economy are increasingly likely to see their bottom lines either positively or negatively impacted by new climate regulations.

As federal lawmakers move forward with drafting a landmark climate bill, the Environmental Protection Agency has issued several proposals that would regulate greenhouse gas emissions from cars and large industrial sources.

The administration has issued a raft of economic assessments of climate legislation that outlines a band of likely carbon prices. That should give companies enough information to brief investors on the risks such policies may pose to their business, some investors say.

Dan Bakal, Ceres' Director of electric power programs, said that while approved shareholder requests aren't binding, "they do have quite an impact, sending a pretty powerful signal to the company that need to take action on an issue."

Bakal said companies such as Alpha Natural Resources (ANR), Consol Energy (CNX) and Foundation Coal - now merged with Alpha - have previously successfully rejected shareholder resolutions seeking more information on regulatory risks.

The SEC guidance follows a series of investor lawsuits against emissions-intense companies demanding that they better reveal the potential impact of climate policies on their operations.

SEC Commissioner Elisse Walters has said the agency is separately considering giving new guidance requiring greater carbon disclosure in regular filings with the Commission.

-By Ian Talley, Dow Jones Newswires; (202) 862 9285; ian.talley@dowjones.com