Elon Reeve Musk (/ˈiːlɒn/ EE-lon; born June 28, 1971) is a business magnate and investor. He is the founder, CEO and chief engineer of SpaceX; angel investor, CEO and product architect of Tesla, Inc.; owner, CTO and chairman of Twitter; founder of the Boring Company and X Corp.; co-founder of Neuralink and OpenAI; and president of the philanthropic Musk Foundation. Musk is the wealthiest person in the world according to the Bloomberg Billionaires Index, and second-wealthiest according to the Forbes's Real Time Billionaires list as of June 2023, primarily from his ownership stakes in Tesla and SpaceX, with an estimated net worth of around $205 billion according to Bloomberg and $211.4 billion according to Forbes.

Musk was born in Pretoria, South Africa, and briefly attended the University of Pretoria before moving to Canada at age 18, acquiring citizenship through his Canadian-born mother. Two years later, he matriculated at Queen's University and transferred to the University of Pennsylvania, where he received bachelor's degrees in economics and physics. He moved to California in 1995 to attend Stanford University. After two days, he dropped out and, with his brother Kimbal, co-founded the online city guide software company Zip2. In 1999, Zip2 was acquired by Compaq for $307 million and Musk co-founded X.com, a direct bank. X.com merged with Confinity in 2000 to form PayPal, which eBay acquired for $1.5 billion in 2002.

With $175.8 million, Musk founded SpaceX in 2002, a spaceflight services company. In 2004, he was an early investor in the electric vehicle manufacturer Tesla Motors, Inc. (now Tesla, Inc.). He became its chairman and product architect, assuming the position of CEO in 2008. In 2006, he helped create SolarCity, a solar energy company that was later acquired by Tesla and became Tesla Energy. In 2015, he co-founded OpenAI, a nonprofit artificial intelligence research company. The following year, he co-founded Neuralink—a neurotechnology company developing brain–computer interfaces—and the Boring Company, a tunnel construction company. Musk has also proposed a hyperloop high-speed vactrain transportation system. In 2022, his acquisition of Twitter for $44 billion was completed.

Valve Corporation, also known as Valve Software, is an American video game developer, publisher, and digital distribution company headquartered in Bellevue, Washington. It is the developer of the software distribution platform Steam and the franchises Half-Life, Counter-Strike, Portal, Day of Defeat, Team Fortress, Left 4 Dead, and Dota.

Valve was founded in 1996 by former Microsoft employees Gabe Newell and Mike Harrington. Their debut game, the first-person shooter (FPS) Half-Life (1998), was a critical and commercial success; with its realism, scripted sequences and seamless narrative, it had a lasting influence on the FPS genre. Harrington left in 2000. In 2003, Valve launched Steam, followed by Half-Life 2 in 2004. With advanced physics systems and an increased focus on story and characters, Half-Life 2 received critical acclaim and sold 12 million copies by 2011. In 2006, Valve released the episodic sequel Half-Life 2: Episode One, followed in 2007 by Episode Two, the multiplayer game Team Fortress 2 and the puzzle game Portal. Portal 2 was released in 2011. In 2013, Valve released the multiplayer online battle arena game Dota 2.

Valve released fewer games in the 2010s and experimented with hardware and virtual reality (VR). They entered the hardware market in 2015 with the Steam Machine, a line of gaming computers, which sold poorly, and released the HTC Vive and Valve Index VR headsets. They returned to the Half-Life series in 2020 with Half-Life: Alyx, their flagship VR game. In 2022, Valve released the Steam Deck, a portable gaming system.