Roundup: ExxonMobil overtaken / Nobel Prize / Emergent Method By Deanna B. Narveson - October 12, 2020 FacebookTwitterLinkedinEmailPrint Big Oil: Chevron Corp. overtook ExxonMobil Corp. as the largest oil company in America by market value, the first time the Texas-based giant has been dethroned since it began as Standard Oil more than… Already an INSIDER? Sign in.