Shares of biofuel company Gevo Inc. soared more than 270% Monday, after the Environmental Protection Agency raised the amount of isobutanol used for on-road use in cars to a 16 percent blend level from a previous 12.5 percent blend level. The approval came at the request of Delaware-based Butamax Advanced Biofuels LLC, a joint venture between BP Plc and DuPont . “At Gevo we have been developing the markets for isobutanol containing gasoline, in particular to meet the demand for the “ethanol free” segment of the gasoline market,” Gevo Chief Executive Patrick Gruber said in a statement. Englewood, Colo.-based Gevo specializes in renewable technology and biofuels, including ethanol. Shares have gained 26% in 2018, while the S&P 500 has gained about 4%. Other biofuel stocks rose in sympathy. Green Plains Inc. rose 1.6%, Rex American Resources Corp. added 3.3% and Aemetis Inc. was up 2.1%.