Forbes recently released its 2012 list of the world's billionaires, so we figured we'd post a list of the public companies in the US that are hundred billionaires. There are currently 24 public companies in the US that are worth more than $100 billion. As shown below, Apple is the biggest at close to $500 billion, followed by Exxon Mobil (XOM) at $400 billion, Microsoft (MSFT) at $268 billion, and IBM at $230 billion. Chevron (CVX), Wal-Mart (WMT), General Electric (GE), Google (GOOG), Berkshire (BRK/B), and Procter & Gamble (PG) round out the top ten.
For each company, we also show what its market cap was ten years ago. Apple (AAPL), now the largest company in the world, was by far the smallest company on the list ten years ago at just $8.7 billion. General Electric (GE) was the largest company on the list ten years ago at $403 billion. GE's market cap has fallen 50% since then.