AP Photo/Ng Han Guan Tesla gained in pre-market trading Tuesday after Goldman Sachs upgraded the electric vehicle maker's stock to "buy" from "neutral" and raised its price target to $780.Strategists believe mainstream adoption of electric vehicles is accelerating, battery prices are falling fast, and government regulations will eventually phase out higher-emission vehicles.Tesla's other clean-energy products, including solar panels and roofs, make for promising opportunities."The energy business should also benefit from the regulatory shift toward carbon reduction and clean energy, and solar market valuations have similarly accelerated," strategists wrote.Visit Business Insider's homepage for more stories.Shares in Tesla jumped on Thursday after Goldman Sachs upgraded its stock to "buy" from "neutral" and boosted its price target to $780, currently the highest on Wall Street.Tesla stock rose as much as 3% in pre-market trading.