June 24 (Reuters) - The spotlight is on chipmaker Micron Technology ( MU ) as it prepares to report earnings, with investors bracing for further volatility following sharp market swings fueled by large flows tied to SpaceX and a two-day boom-bust in semiconductor stocks.

Last June, Micron was a well-known if somewhat obscure company with a market value of $136 billion and a long history, but not necessarily one whose quarterly earnings reports caught investors' fancy.

Fast forward a year, and Micron is one of the stars of the technology rally that has sent chipmakers around the world soaring, igniting a fresh trading frenzy even after a dozen or more months of AI excitement. Micron is up 761% from a year ago, boosting its market value to $1.19 trillion, placing it among the top U.S.-listed companies and surpassing Walmart ( WMT ) and Intel.

That has proved to be a windfall for its investors but potentially adds to the stress portfolio managers and other market mavens face over how the company's results will turn out on Wednesday, as they try to work out what sparked the chipmaker selloff and gauge an unsettling debut for the new Federal Reserve chair.

The Nasdaq has fallen more than 5% after a record run and investors say the market swings have at times been surprisingly abrupt, leaving them to wonder which shoe could drop next.

"It's that question of whether it sets off a domino effect or whether it's just a little step back and then it takes a couple of steps forward again," said Michael Field, chief equity market strategist at Morningstar.

The parabolic gains in Micron and shares of other semiconductor stocks, combined with the slate of mega IPOs this summer, are generating concerns about market euphoria and a potential topping out of the major indexes.

At the same time, large expected earnings gains stemming from massive AI capital spending are sustaining the market advance, but without necessarily extending too obviously into what is called "bubble territory."

"Part of the move in tech reflects funds taking profits and recognising that the risk-reward profile has shifted, particularly given the crowded positioning across parts of the global AI infrastructure and memory complex," said Chris Weston, head of research at Pepperstone.

PRICED FOR PERFECTION

The technology selloff earlier in the week spread globally, with the tech-heavy stock markets of South Korea and Taiwan also slumping.

Large memory-chip players SK Hynix and Samsung Electronics recently soared above $1 trillion in market capitalization, becoming among the first few Asian companies to notch the milestone.

Micron is expected to post third-quarter results after the closing bell on Wednesday. Analysts, on average, expect the Idaho-based company to post a profit growth of more than 1,000% and a near 285% jump in revenue, compared with a year ago.

Micron's chips are tightly integrated into AI systems and analysts expect demand for memory chips to outpace supply for at least the next two years.

"Micron is taking on an Nvidia type of market dynamic," said Kenny Polcari, chief market strategist at Slatestone Wealth.

"When a stock is priced for perfection, perfection becomes the minimum requirement. Anything less - softer guidance, slowing demand trends, margin pressure, or even a cautious tone from management could trigger a meaningful pullback."

Micron's shares rose 3.8% in premarket trading. Its forward-looking price-to-earnings ratio, a valuation metric, has dropped sharply to 8.59 as shares touched record highs and analysts ramped up their earnings expectations.