NEW YORK - Firms find that investors penalize their stock less for high greenhouse gas emissions if they voluntarily disclose that data, researchers at Lazard's climate center said on Friday.

Regulators in the United States are working on rules for how companies provide information to help investors gauge their impact on the environment, as part of a broad drive to stem climate change from activities such as the use of fossil fuels.

As investors relied on "a patchwork of voluntary climate-related communications" between 2011 and 2020, the Lazard bankers and professors from the Harvard Kennedy School, Columbia University and London's Imperial College found that Russell 3000 companies seem to be better off being up-front about their emissions.

In general, 10% higher greenhouse gas emissions from a firm's own operations, known as Scope 1, could be expected to shave a little more than 1% over its price-to-earnings (P/E) ratio, a commonly used measure of a stock's value.

But if the company disclosed its Scope 1 emissions, its P/E ratio would be expected to be 0.6% higher than it would have been otherwise, effectively offsetting 48% of the discount that had been applied due to the higher emissions. For energy companies the effect was more pronounced: Disclosure actually increased their P/E measure by 0.8%.

The most likely explanation, Lazard found, is that a lack of disclosure prompts investors to price in the uncertainty of an estimate they may have to make on their own.

"People might assume the worst if you don't disclose," said Peter Orszag, chief executive of financial advisory at Lazard.

Many firms have pledged in recent years to reduce their carbon emissions, but the report found this had little observable impact on their valuations.

This kind of pledge could require spending money in the near term to phase out carbon or buy offsets, but the report found the most likely explanation to be linked to another finding: More than half the companies sampled are not on track to meet their own targets.

"Investors may not interpret pledges as bearing material weight, but rather as ... bolstering public relations," the report said.

(Reporting by Isla Binnie; Editing by Leslie Adler)