NEW YORK CITY, New York: SpaceX shares fell sharply on June 18 as investors pulled back from the buying frenzy that followed the company's record-breaking stock market debut, trimming some of the gains that briefly pushed the firm into the ranks of the world's most valuable companies.

The stock dropped more than 6% in afternoon trading and was last down 6.5% at $178.50, extending losses from the previous session. Despite the decline, shares remained more than 30% above their initial public offering price of $135.

If the losses hold through the close, SpaceX's market value would fall by more than $150 billion, reducing its valuation from the levels reached during its post-listing surge.

"Given the magnitude of the IPO and the strong initial performance, some degree of profit-taking is not surprising," IPOX Schuster analyst Kat Liu said.

"This has been a particularly eventful and shortened trading week for the largest IPO in history," she added.

The pullback was not limited to SpaceX. Shares of other U.S. space companies also declined, with Rocket Lab and Planet Labs falling around 3%, while AST SpaceMobile and Intuitive Machines dropped approximately 7% and 3%, respectively.

SpaceX's stock had rallied strongly following its Nasdaq debut last week, helping lift the company's valuation above $2 trillion. The rapid rise fueled enthusiasm among retail investors and cemented Elon Musk's position as the world's first trillionaire.

However, analysts and fund managers have repeatedly warned that the stock could experience significant volatility because of its relatively small public float and lofty valuation.

Retail investors were among the biggest drivers of the initial rally. According to Vanda Research, individual investors purchased more than $300 million worth of SpaceX shares over the previous three trading sessions.

That momentum appeared to fade on June 18, with net retail purchases totaling just $9.1 million as of 2 p.m. ET.

Investors are also weighing whether SpaceX's valuation can be supported by its long-term growth plans, particularly its ambitious expansion into artificial intelligence.

Earlier this week, the company announced plans to acquire Anysphere, the startup behind the AI coding assistant Cursor, in a stock transaction valued at $60 billion. The deal is intended to strengthen SpaceX's position in the growing market for enterprise AI tools.

At the same time, the company is seeking additional funding to support its expansion plans. A source familiar with the matter said SpaceX's bankers are preparing to meet investors as early as next week regarding a bond offering worth at least $20 billion.

The proposed fundraising effort would help finance the company's AI ambitions as it seeks to expand beyond its core businesses in rockets, satellite communications and space technology.