The biggest, most widely-held shares

The biggest companies by market value are also, quietly, the ones most people already own: a global or S&P 500 index fund holds them in proportion to their size, so the largest names make up the largest slices of millions of portfolios.

Being the biggest today is a fact, not a promise - giants can stumble and today's leaders aren't always tomorrow's. But these are the names it's most useful to understand first, because you likely own a piece of many of them already.