(Reuters) - Tesla shares rose 6% on Monday, approaching a $500 billion market value and extending gains to 27% since news a week ago that the electric car maker will debut in the S&P 500 in December, forcing index funds to buy billions of dollars of its stock. Up about 500% in 2020, Tesla has become by far the world’s most valuable automaker, despite production that is a fraction of Toyota, Volkswagen or General Motors. Graphic: Tesla in the S&P 500: small profits in a big pond, Tesla is now five times more valuable than GM and Ford combined and the latest rise in the Silicon Valley automaker’s shares came after Wedbush analyst Daniel Ives bumped his price target to $560 from $500. While he maintained his neutral rating, Ives also said the stock could hit $1,000 in a “Bull Case”, reflecting steeper demand for electric vehicles in coming years. However, the median price target of analysts covering the stock is $385, about 26% below the $519 it hit on Monday, reflecting a belief among many on Wall Street that Tesla’s shares have become overvalued. Index funds trying to match the S&P 500’s performance will have to buy more than $50 billion of Tesla’s stock ahead of its inclusion on Dec. 21, and Goldman Sachs estimated last week that actively managed mutual funds could buy another $8 billion. Now worth $491 billion, Tesla is Wall Street’s seventh most valuable company, just behind Berkshire Hathaway and just ahead of Visa, Refinitiv data shows.