Micron Technology’s shares tumbled on Friday, giving back some of the gains from a post-earnings rally, as the memory chipmaker looked to wrap a rocky week of trading that has seen big swings.

The stock sank 4% as other tech firms also struggled. Intel fell 3%, Arm shed 4%, and Marvell declined 4%.

Investors remain wary of the rising costs of artificial intelligence infrastructure, with the sell-off reverberating across global markets following a New York Times report that OpenAI is considering pushing back IPO timing to next year.

In Europe, key chip stocks also saw losses.

ASML was down 2.2%, Infineon fell 3.7%, ASM International dropped 2.8%, ST Microelectronics lost 3.3%, and Be Semiconductor fell 2%. Japanese conglomerate Softbank led losses in Asia and plunged more than 12%.

Micron’s third-quarter revenue more than quadrupled to $41.46 billion, up from $9.3 billion a year prior, it reported on Wednesday, beating analysts’ expectations. It’s projecting revenue of around $50 billion for the current quarter, compared with $11.3 billion a year earlier. The company’s stock soared more than 15% on the day and is up 863% over the past year.

As major hyperscalers build out AI infrastructure, including data centers, they’re requiring huge amounts of memory chips that they’re purchasing from Micron.

That surge in demand is reducing the supply of memory for other devices like smartphones, PCs, and more, which has pushed prices higher and lifted Micron’s earnings.

SpaceX shares dropped 9% on Thursday, as the stock’s recent rally showed signs of cooling following a record-breaking IPO last week.

Elon Musk‘s space and AI company saw its stock surge more than 40% after its historic debut last week, which offered shares at a set price of $135.

Investor bullishness showed signs of waning on Wednesday, however, as shares sank 5%.

SpaceX immediately became one of the world’s most valuable companies after listing, with its market cap surpassing Amazon and — briefly — Microsoft. Its valuation sat just below Amazon at $2.52 trillion at market close on Wednesday.

The rocket maker announced Wednesday that it’s adding Musk’s longtime friend and ally, Roelof Botha to the board.

Botha will serve as an independent director and a member of the company’s audit committee, starting immediately. Botha becomes the eighth board member at SpaceX, where Musk serves as chairman, in addition to his roles as CEO and technology chief.

Musk ​controls more ⁠than 82% of voting rights at SpaceX and owns shares in the company worth over $1 trillion. The governance model gives outside shareholders little ability to exert influence.

Posting on X on Sunday, Musk said that the company “might be able to reach approximately” $1 trillion revenue in 2030.

— CNBC’s Lora Kolodny helped contribute to this report.

Marvell shares popped 18% on Friday as the company posted an earnings beat and issued strong guidance, expecting strong artificial intelligence demand to continue.

The semiconductor company reported adjusted earnings of 80 cents per share for the quarter, exceeding the 79 cents per share expected by analysts polled by LSEG. The company reported $2.2 billion in fourth-quarter revenue, topping a forecast of $2.1 billion.

“Look at our results that we’re guiding. Look at our outlook for this year. Look at our outlook for next year. Do you see me blinking? You don’t,” CEO Matt Murphy told analysts on the earnings call.

Murphy said in a release that the company expects year-over-year revenue growth to accelerate in each quarter of 2027.

For Q1 2027, the chipmaker expects revenue of $2.4 billion, +/-5%. Wall Street expected $2.27 billion.

The company’s revenue for data centers in fiscal 2026 surpassed $6 billion, an increase of 46% from last year.

CNBC’s Kristina Partsinevelos contributed to this report.