A Texas judge has left alive nearly all of a federal class action accusing Exxon Mobil Corp. and former CEO Rex Tillerson of securities fraud related to its alleged misstatements on the value of oil and gas reserves and the potential costs of paying carbon taxes, which ultimately led to its stock plummeting by 20 percent, erasing billions of dollars in value.

Ruling on Exxon Mobil’s motion to dismiss, U.S District Judge Ed Kinkeade of Texas’ Northern District Court struck portions of two expert opinions attached to the amended complaint, but said the plaintiffs sufficiently pleaded their allegations that the energy giant knowingly kept its stock inflated by refusing to write down the value of its assets, even as competitors were downgrading their own values as the price of oil began to crater in 2014.