SpaceX (NASDAQ: SPCX) shares tumbled more than 6% on Thursday as the euphoria surrounding the largest IPO in history showed signs of fading.

The stock was last trading down 6.5% at $178.50, extending a nearly 5% decline from the previous session, though it remained more than 30% above its $135 offering price.

If the losses held through the close, SpaceX’s market capitalization of $2.52 trillion would shed more than $150 billion in a single trading day.

IPOX Schuster analyst Kat Liu said the pullback was not entirely unexpected given the scale of the debut and the strength of the initial rally.

“Given the magnitude of the IPO and the strong initial performance, some degree of profit-taking is not surprising,” Liu said.

Liu also noted the unusual circumstances surrounding the trading week, saying, “This has been a particularly eventful and shortened trading week for the largest IPO in history.”

Shares of other U.S. space companies were caught in the downdraft, with Rocket Lab and Planet Labs each dropping around 3%, while AST SpaceMobile fell approximately 7% and Intuitive Machines declined around 3%.

Retail investor enthusiasm, which had driven over $300 million in net purchases across the first three sessions, cooled sharply on Thursday, with only $9.1 million in net purchases recorded as of 2:00 p.m. ET, according to Vanda Research.

Analysts and portfolio managers have cautioned that SpaceX’s relatively small public float and elevated valuation make early volatility an expected feature of the stock’s life as a public company.

SpaceX’s valuation had surged past $2 trillion following its blockbuster Nasdaq debut, with shares soaring in the first two trading days before investors began scrutinizing whether its costly AI expansion could justify such a rich price tag.

On Tuesday, the company announced it would acquire Anysphere, the startup behind the popular AI coding agent Cursor, for $60 billion in stock, a move aimed at strengthening its foothold in the enterprise AI tools market.

Adding to its ambitious growth agenda, SpaceX’s bankers are preparing to meet investors as early as next week to discuss a bond offering of at least $20 billion, according to a source, as the company seeks to fund its expanding AI operations.