STORY: SpaceX has confidentially filed for an initial public offering, according to a person familiar with the matter, setting the stage for what could be one of the most closely watched market debuts.

The potential listing is expected to draw significant investor attention, as the company looks to enter public markets after years of rapid growth.

McMillan says the company has evolved into a real, cash-generating business.

"I think what's interesting about SpaceX is it's such a unique moat for a company," he said. "It literally launched as a moonshot years ago and now all of a sudden they've got real margins, a real business."

"When you look at StarLink, for example, which is roughly two thirds of their revenue, that's a cash-flow machine," McMillan added. "It's got huge margins, so it's a really compelling story."