Tesla Motors Inc (NASDAQ:TSLA) shares have soared an eye-popping 620% over the past 12 months. As a result, its founder CEO Elon Musk’s net worth has swelled more than three times to $8.4 billion, according to Forbes’ latest list of billionaires. Now, Musk is only behind BMW’s heirs in the list of world’s richest automotive titans. Johanna Quandt and her children Susanne Klatten and Stefan Quandt collectively own about 50% stake in the German luxury automaker. Interestingly, BMW is trying to challenge Tesla in the electric vehicle market with its i3 and i8 cars.

Elon Musk Tesla Motors

Tesla CEO closing in on BMW heirs

These three German automotive billionaires inherited their fortunes when Herbert Quandt, husband of Johanna, and father of Susanne and Stefan, passed away. Herbert Quandt is well-known for turning around BMW’s fortunes when it was on the verge of bankruptcy in the 1960s. Strong vehicle sales fueled BMW’s stock price, making them all richer. Johanna Quandt is worth $12.8 billion, her daughter Susanne Klatten has a fortune of $17.4 billion, and her son Stefan is worth $14.9 billion, according to Forbes.

Right behind them is South African-born founder of Tesla Motors Inc (NASDAQ:TSLA). Investors have showed faith in him and his Model S sedan, which has been named the best car of the year 2013 by Consumer Reports. Recently, Musk unveiled plans to build a massive gigafactory to bring down the costs of advanced lithium-ion batteries. These batteries will be used in the mass market electric vehicles Tesla plans to produce in the future. Only two-thirds of Elon Musk’s wealth comes from Tesla Motors. The increase in his wealth was also helped by a 340% gain in SolarCity Corp (NASDAQ:SCTY), where he serves as chairman. Musk’s privately-owned SpaceX is also estimated to be worth about $4 billion.

Top ten automotive titans

The richest automotive titans included the chairman of China’s Great Wall Motor, Wei Jianjun, who has a fortune of $6.9 billion. Wang Chuanfu, chief of Warren Buffett-backed BYD is worth $4.3 billion. Chung Mong-Koo of South Korea’s Hyundai Motor has a net worth of $6.8 billion. Bruce Halle, founder of Discount Tire store chain, has a fortune of $5 billion. Luo Jye, chairman of Taiwan’s Chen Shin Rubber is worth $4.4 billion. Pakistan-born Shahid Khan also appeared among the top ten auto titans. Khan is the founder of automotive parts supplier Flex-N-Gate. He is also the owner of Jacksonville Jaguars football team.

Tesla Motors Inc (NASDAQ:TSLA) shares surged 2.08% to $255.74 at 13:04 PM EST.