When SpaceX struggled to stay alive in 2008 after three failed rocket launches, few investors wanted to touch the company...

With SpaceX seeking a valuation of nearly $1.8 trillion in IPO, early bets are poised to generate some of the biggest paper gains in venture capital history.

In the old days, companies went public early to access cash to grow. These days, soon-to-be-public companies are already flush with cash from private finance.