SpaceX stock fell 16% in four days after its IPO debut, erasing most early gains—but the company still trades near IPO price, leaving investors to weigh whether the $2 trillion（約320兆円） valuation fits its business.

What happened

SpaceX shares opened at $150 (above the $135 IPO price) and climbed for three days, reaching over $160 before reversing course. A 16% plunge on Monday brought the stock back to $155 per share, cutting the company's valuation from over $2.7 trillion（約430兆円） to barely $2 trillion（約320兆円） in less than a week.

Why it matters

The sharp swing highlights tension between SpaceX's stated potential—Elon Musk argues the company has a $28.5 trillion（約4600兆円） total addressable market while generating less than $20 billion（約3.2兆円） in sales today—and its current valuation multiples (125 times sales). Investors must decide whether the company's dual focus on space operations and artificial intelligence justifies the premium price, or whether cheaper alternatives like Rocket Lab or Nvidia offer better value for those seeking exposure to either sector.

What to watch

At $154–155 per share, SpaceX stock is trading only about 3% above the IPO open price, offering investors a chance to buy near levels they might have missed on Day One. The real question for prospective buyers is whether SpaceX fits their investment thesis better than other space or AI stocks at any valuation.