Elon Musk—also known as the "real-life Tony Stark"—is a self-made billionaire, engineer, scientific visionary and investor who has managed to capture the imaginations of the science, tech and finance communities. Musk serves as CEO of two large enterprises, Tesla Motors, Inc. (NASDAQ: TSLA) and SpaceX, which is a private company. A sizable amount of his fortune was built on 20 plus years of selling or taking his previous companies public.

In 1999, Musk sold his first company, Zip2, to Compaq for $307 million in cash and $34 million in stock options. He invested money from the sale to found X.com, which became PayPal Holdings, Inc, (NASDAQ: PYPL) and was eventually purchased by eBay Inc (NASDAQ: EBAY), in 2002 for $1.5 billion. He became an investor in Everdream Corporation in 1998 before Dell acquired it in 2007.

Similarly, Musk invested in the artificial intelligence company DeepMind Technology prior to a 2014 buyout by Google.

Tesla

Elon Musk is Tesla's largest investor, owning approximately 22% of shares. He is also the CEO and lead architect of the firm and original founder, coming in through an initial round of funding when the company first launched.

Aside from his current holdings in Tesla, Musk has been given a deferred compensation plan that will be paid out only if the company meets certain performance goals. The value of the payout is $2.6 billion in stock options as of 2018 stock value when the deal was finalized. However, if the payout occurs in the future, the value is estimated to be $56 billion. Musk does not receive any salary as CEO of Tesla.

SolarCity

SolarCity, a solar panel firm founded by Musk's cousin, was acquired by Tesla in 2016 for $2.6 billion. Ever since the acquisition, the overall business of SolarCity has diminished, as Musk directed a significant portion of its activities toward the development of the Model 3 automobile for Tesla.

It has since come to light that Musk acquired SolarCity in a kind of bailout as SolarCity was having liquidity problems at the time and that Musk allegedly misrepresented the firm's financial health. SolarCity now operates under the energy arm of Tesla and Musk maintains optimistic on the growth of the energy division.

SpaceX

Elon Musk is the majority owner of SpaceX, holding about 54% of the private company, which is valued at approximately $33.3 billion. The U.S. government hires SpaceX via government contracts through N.A.S.A. and the U.S. Air Force for a variety of services, such as satellite launches. SpaceX has been slowly taking away government contracts from the established players in the market, primarily Boeing and Lockheed. In addition to government contracts, SpaceX also provides commercial launches to companies.

SpaceX has created and launched a spacecraft to the International Space Station and has launched its own flight-ready rockets with over 100 missions to its name. Currently, SpaceX is working on an ambitious new project entitled Starlink, which aims to cover the world in satellites to provide fast and reliable Internet to the earth's population.

Property

The entirety of Elon Musk's real estate portfolio is not fully known; however, he does own a few homes in Los Angeles that have been purchased for approximately $55 million.