You can ignore AI giants like SpaceX, but your 401(k) won’t

While you might want to ignore all the hubbub around SpaceX, Elon Musk and IPOs, your 401(k) likely can’t.

SpaceX is now worth $2.1 trillion after its stock launched 19.2% higher in its debut on Wall Street. Whether or not you believe it deserves to be worth more than Exxon Mobil, Bank of America and Coca-Cola combined, the collective market does. And if SpaceX maintains that big a value, it will join some high-profile stock indexes.

Many of these indexes don’t care about how realistic a company’s growth plans are or who its CEO is. They’re simply trying to show how slices of the market, or the whole thing, are performing. And if SpaceX is big enough to meet the qualifications to join those indexes, whether it’s in a few weeks or a year, it will gain entry.

That matters for investors and their 401(k) accounts because they’re depending more than ever on funds that simply mimic these indexes. It’s a lower-cost way to invest, allowing savers to keep more of their investments. Partly because of that, such index funds have usually prov...