Splashy initial public offerings often skyrocket early on, only to return to earth with a thud, Wall Street analysts say.

The S&P 500 index is sticking to its rules, but other indexes are making changes to add SpaceX as quickly as possible.

Stock compensation is rocket fuel for employees of SpaceX. Its IPO will make many of them millionaires. Here's what I learned about their stock comp in the IPO filing.

Wall Street is moving to stuff SpaceX shares into small investors' portfolios, exposing them to a potentially overpriced stock.

Shares priced at USD 135 each, valuing rocket and satellite firm at USD 1.77 trillion

Three of the world’s largest and most consequential private companies—SpaceX, Anthropic and OpenAI—are preparing to go public in the same year.

"MegaCap IPOs have the potential to achieve immediate and material investor ownership, trading liquidity, and market relevance," S&P Dow Jones Indices said. It went on to say that the current index rules could "prevent such IPOs' timely index inclusion and impact the overall index's effectiveness as a benchmark."

Elon Musk's SpaceX — rocket manufacturer, satellite internet service provider, AI firm and owner of X (aka Twitter) all rolled into one — has officially set a record for the biggest IPO in history with its initial stock pricing.

The soon-to-be-public company's size and quick inclusion into major market indexes are unprecendented.

Historical data suggest that major IPOs don't usually flag a bull market peak in the year that follows. SpaceX is poised to launch the biggest IPO ever when it begins trading this Friday. But a recent analysis from Canaccord Genuity shows that broad stock market averages typically tend to outperform big IPOs after a year.

This is happening at a time when IPOs are already having a powerhouse year. According to Renaissance Capital, $34.2 billion has already been raised through May 31, up 163.9% from the same period a year ago.

A recent report from Morningstar, for example, calls the IPO stock "significantly overvalued." The firm estimates that SpaceX's true value is currently around $780 billion -- less than half the company's intended valuation.