SpaceX‘s IPO has already checked the obvious headline box. The company reportedly attracted roughly $150 billion in investor orders ahead of Wednesday’s close of the order books, making it one of the most sought-after public offerings in market history.

But while much of Wall Street is focused on the sheer size of the demand, another number may matter more: how few shares are actually available.

That’s because investors aren’t just chasing a space company. They’re chasing scarcity.

Tiny Float, Massive Demand

Unlike many blockbuster IPOs that put a meaningful chunk of the company into public hands, SpaceX is expected to float only a small percentage (less than 5% of shares outstanding) of its total shares.

That creates a simple but powerful dynamic. Demand can surge into the tens or even hundreds of billions of dollars, but the supply of stock remains tightly constrained.

The result is a setup that some investors describe as a classic scarcity trade, a situation where the limited availability of an asset becomes part of the investment thesis itself.

The phenomenon isn’t new. Highly anticipated ...