DALLAS — The New York attorney general said Exxon Mobil is misleading investors about how it estimates the potential cost of climate-change regulations.

The New York Attorney General Eric Schneiderman said in a court filing Friday that Exxon’s calculations “may be a sham.” He said the oil company told investors it used one estimate of regulatory costs on projects, but then applied a lower estimate. That makes some of its oil and gas projects look like they will be more profitable and less risky.

The accusation surfaced the same week that shareholders pressed Exxon to disclose more details about how regulations designed to limit climate change will affect its business.

An Exxon spokesman said the attorney general’s charges were inaccurate and his investigation was motivated by politics and publicity.

Schneiderman made the accusations as he asked a state court to force Exxon Mobil Corp. to turn over more documents and witnesses for his investigation into the Texas-based oil giant.

Exxon has said that since 2007 it has applied a “proxy cost of carbon” when judging oil and gas projects. That is an estimate of the future costs of complying with regulations to limit greenhouse gas emissions from burning fossil fuels like oil and natural gas.

Schneiderman charged that while the company said in 2014 that the additional regulatory cost of fossil fuel could approach $80 per ton of greenhouse gas emissions by 2040, he found evidence indicating that Exxon privately used lower figures but never told investors about the “secret internal” calculations.

The carbon-cost estimates are important because understating regulatory costs could lead the company to push ahead with financially risky projects. Schneiderman said if Exxon had used its publicly reported estimate instead of the lower internal figure, at least one oil-sands project in Canada would have been projected to lose money.

Exxon spokesman Scott Silvestri said documents already turned over to Schneiderman show that the company has accurately described its use of carbon-cost estimates.

On Wednesday, investors holding 62 percent of shares cast voted for a resolution to push the company to disclose more about how climate-change regulations will affect its business. The Exxon board opposed the nonbinding resolution.