Robert McTamaney of Carter, Ledyard & Milburn LLP, who wasn’t involved in the case, said the ruling was “a very welcome departure from the long line of cases and forced settlements under New York’s Martin Act.” In an email, he called the act “a truly atrocious law which alleges liability without any proof of intentional fraud, or reliance by anyone, or any of the essential elements of a federal law fraud case.”

The decision “just shows what many suspected all along,” said Brooklyn Law School professor James Fanto, that the lawsuit “was nothing more than an enforcement action designed to harass the defendant and to please the attorney general’s political base.”

The AG said she was undaunted.

“For the first time in history, ExxonMobil was compelled to answer publicly for their internal decisions that misled investors,” James said in a statement. “The oil giant never took seriously the severe economic impact that climate change regulations would have on the company, contrary to what they were telling the public.”

Despite the ruling, she said, “we will continue to fight to ensure companies are held responsible for actions that undermine and jeopardize the financial health and safety of Americans across our country, and we will continue to fight to end climate change.”

Asked about a possible appeal, a spokesman for James said the office is still reviewing Ostrager’s decision.

Ostrager said his opinion wasn’t intended to absolve Exxon from responsibility for contributing to climate change through the emission of greenhouse gases.

“Exxon Mobil does not dispute either that its operations produce greenhouse gases or that greenhouse gases contribute to climate change,” the judge wrote. “But Exxon Mobil is in the business of producing energy, and this is a securities fraud case, not a climate change case.”

Exxon got a hint of victory on the last day of the trial when a lawyer for the attorney general said during closing statements that the state was dropping the two most damning of four claims without explanation. The abandoned claims, which had been crucial elements of the case, held that Exxon’s calculations were part of a scheme to mislead and that investors had relied on them when buying the company’s stock.

After the AG’s retreat, what remained for Ostrager to decide was whether Exxon had violated the Martin Act by issuing public statements about proxy costs that were materially misleading. The state couldn’t show that it had.