(Updates with preliminary closing prices 04:00 p.m. ET/2000

GMT)

By Sinéad Carew and Bansari Mayur Kamdar

March 21 (Reuters) - Wall Street's three major stock

indexes on Thursday registered record closing highs for the

second day in a row after the Federal Reserve reassured

investors about the prospects for rate cuts this year while chip

stocks rallied after Micron Technology's ( MU ) upbeat forecast.

Shares in Micron Technology ( MU ) rallied sharply after

hitting an all-time high following a surprise quarterly profit

and its forecast of third-quarter revenue above estimates.

Broadcom ( AVGO ) also climbed rapidly after TD Cowen

upgraded its rating of the stock to "outperform". Shares in

Nvidia ( NVDA ) were also a big boost while the Philadelphia

Semiconductor index rallied.

U.S. stock indexes had boasted record closing levels on

Wednesday after U.S. central bankers kept borrowing costs

unchanged and indicated they still expect to ease interest rates

by three-quarters of a percentage point by the end of 2024.

"Earnings results are keeping semiconductors as market

leaders but more broadly a risk on mode has stemmed from the

dovish Fed on Wednesday," said Matthew Miskin, Co-Chief

Investment Strategist at John Hancock Investment Management.

Fed Chair Jerome Powell said in a press conference after the

policy meeting on Wednesday that inflation reports "haven't

really changed the overall story, which is that of inflation

moving down gradually on a sometimes bumpy road to 2%."

But John Hancock's Miskin questioned whether the Fed is

being overly optimistic about inflation and rate cuts.

"They're opening to door to let inflation risk seep back

into the market. It's not there yet but it's a risk that could

come later this year," he said.

In the meantime, however, economic data released earlier on

Thursday was adding to investors' bullish moods.

The number of Americans filing new claims for unemployment

benefits unexpectedly fell last week, while sales of previously

owned homes increased by the most in a year in February, signs

the economy remained on solid footing in the first quarter.

"This economy continues to defy expectations and markets are

loving every minute of it," said Miskin.

According to preliminary data, the S&P 500

gained 16.37 points, or 0.31%, to end at 5,240.99 points,

while the Nasdaq Composite gained 30.65 points, or

0.19%, to 16,400.05. The Dow Jones Industrial Average

rose 266.62 points, or 0.67%, to 39,778.75.

The three major indexes hit fresh intra-day record highs and

the Dow neared its 40,000 level milestone.

Apple ( AAPL ) bucked the market trend however with a sharp

decline after the U.S. Department of Justice sued the iPhone

maker, the first major antitrust effort against the company by

the Biden administration, alleging it monopolized smartphone

markets.

Shares in IT services provider Accenture tumbled

after it cut its fiscal-year 2024 revenue forecast, with

economic uncertainty prompting its clients to cut consulting

services spending.

Reddit shares started trading on the New York Stock

Exchange at $47, which was 38% higher than its initial public

offer price of $34.