Shares of Tesla Inc. /zigman2/quotes/203558040/composite TSLA -1.21% surged 4.4% in premarket trading, extending earlier gains, after Piper Sandler analyst Alex Potter became the second-most bullish on the Street, citing a more upbeat outlook on Tesla Energy and Chief Executive Elon Musk's stock-based compensation package. Potter raised his price target to $515 from $480, while reiterating the overweight rating he's had on the stock for at least the past three years. Of the 37 analysts surveyed by FactSet, Potter is now just the third with a target of at least $500, behind the $800 target of Global Equities Research and just ahead of Jefferies' Philippe Houchois's $500 target. Potter said he now expects Tesla's energy business to eventually exceed $200 billion a year in revenue. He also laid out his forecasts for stock-based compensation expenses, given concerns recently raised in a report in The Wall Street Journal that Musk's stock options awards could cost the company from being included in the S&P 500 /zigman2/quotes/210599714/realtime SPX +0.34% . "Importantly, the total expense associated with Musk's plan is known (~$2.3B), so the main question regards the 'timing' of these expenses," Potter wrote in a note to clients. Wedbush's Dan Ives also raised his stock price target on Tesla on Friday, but kept his rating at neutral. The stock has soared 110.9% over the past three months through Thursday, while the S&P 500 has gained 7.8%.