Many of the world's largest companies are doing a poor job of preparing for the business impact of global warming, a report issued yesterday by investor, environmental and public interest groups said.

Most of the 20 corporate giants discussed, including leaders in the oil, auto and utility industries, are also failing to disclose to investors enough about the financial risks they face from climate change, according to the report, which was prepared by the Investor Responsibility Research Center in Washington.

None of the companies have produced dollar estimates of the potential costs or benefits of climate change, like more extreme weather, or of the financial impact of changing regulations on carbon emissions, the report said. And eight companies, including General Electric, General Motors and Exxon Mobil, made no mention of climate change in filings last year with the Securities and Exchange Commission.

"We are not talking about issues that are 50 years out," said Mindy Luber, executive director of the Coalition for Environmentally Responsible Economies, which commissioned the study. "We are seeing inadequate board reviews in many, many companies."

The study rated the companies in 14 categories covering the oversight of climate-change issues by corporate boards and progress in setting performance goals as well as disclosure. Two foreign oil companies, BP and Royal Dutch/Shell, were the only ones credited with activity in all 14 categories. The worst performers, including Exxon, G.E. and TXU, an energy services concern, have reported just four of the practices the report identified as prudent.

The companies discussed were allowed to review the parts of the report describing them before publication, but did not necessarily accept the conclusions. Exxon Mobil, for example, said yesterday that it was "adequately addressing the potential risks of climate change" and that its shareholders showed their satisfaction by voting down a resolution at this year's annual meeting requesting a board report on the subject.

Dan Cogan, deputy director for social issues at the investor responsibility center, said, "We gave credit for minimal action, so the relative rankings are more important than the actual scores." The center advises pension funds and others on corporate governance and social issues affecting companies.

With a few notable exceptions, like Alcoa and DuPont, Mr. Cogan said, American companies seem to be discounting the threat of climate change to their businesses more than their overseas competitors.

While better disclosure will help investors, especially those like pension funds with longtime horizons, it could also stimulate companies to move much faster to reduce carbon dioxide emissions that contribute to climate change, Mr. Cogan said. Emissions of toxic substances plummeted when companies had to start reporting them publicly to the Environmental Protection Agency, he noted. The report is available at www.ceres.org and www.irrc.org.