Elon Musk, the billionaire Internet, clean energy and rocket entrepreneur who made his initial fortunes in the internet business, most noticeably via his interest in the sale of the Paypal business, has just added to his wealth via the public sale of the solar generation leasing firm, SolarCity, in which he had a shareholding.

After the Initial Public Offering (IPO) of stock the price of the shares on the first day closed at $11.79, up 47 per cent from the initial share sale price of $8.  As a result, the value of Musk’s shares in the SolarCity firm where he also is Chairman, went up by $70 million from $150.8 million to circa $220 million.  Musk also used the sale to slightly increase his total shareholding in the firm.

Musk previously reached “billionaire” status as the result of his financial interest in the Tesla Motors electric car firm (where he is CEO) whose IPO in 2010 caused the valuation of Musk’s own shares in Tesla to be counted as being in excess of $1 billion. 

Elon Musk has now declared that he is planning an IPO for Space Exploration Technologies (SpaceX) which could occur as early as the latter half of 2013. 

“SpaceX will go public at some point, as I think it should ultimately be owned primarily by the public.” he reportedly said in a tweet to his fans.   Musk however remains fearful of going fully public with SpaceX stock as he noted that publically owned firms do not always survive well in the longer term.