April’s news headlines were dominated by the war in Ukraine, inflation – and Elon Musk’s bid to buy Twitter. The saga ended Monday, when Twitter accepted Musk’s buyout bid in a deal worth about $44 billion, with Musk acquiring the rest of Twitter’s stock that he doesn’t already own for $54.20 a share.

The Tesla and SpaceX CEO – and the world’s richest person – has already disrupted the automotive, transportation, and aerospace industries. He has a footprint in health care, AI, infrastructure, energy, and telecommunications. And now he has set his sights on social networking. Perhaps it is no wonder he is projected to be the world’s first trillionaire. (These are the richest Americans of all time.)

To determine the companies Musk is or has been involved in, 24/7 Wall St. reviewed regulatory filings, media reports, online encyclopedias, and other knowledge bases. Companies are listed alphabetically.

By far, Tesla and SpaceX are Musk’s largest companies, worth a trillion and $100 billion, respectively. Twitter will be the third, right now worth nearly $40 billion. To buy Twitter, Musk has created three companies: X Holdings I, X Holdings II, X Holdings III. He may want to shuffle his enterprises under these umbrellas. (Tesla models are among the 25 best-selling American cars.)

Click here to see all Elon Musk’s companies

In addition to the companies listed, Musk has also invested in the now Google-owned AI company DeepMind and neurotechnology company NeuroVigil, and has been involved in cryptocurrency, affecting the price of dogecoin and other altcoins with his tweets. In general, his reach and influence on Twitter – where he has more than 85 million followers – is huge. His influence outside of Twitter is by no means small either.