(Updates with preliminary closing data 04:00 p.m ET/ 2000 GMT)

By Sinéad Carew and Bansari Mayur Kamdar

March 18 (Reuters) - Wall Street's main indexes advanced

on Monday, with megacap growth stocks such as Alphabet and Tesla

supporting a rebound in technology-heavy Nasdaq while investors

also waited for the U.S. Federal Reserve's meeting this week.

Google's parent Alphabet provided a sizeable boost

to the market after a media report that Apple ( AAPL ) is in

talks to build Google's Gemini AI engine into the iPhone.

This boosted the communication services sector,

which lead gains among the 11 major S&P 500 sectors and hit its

highest level since Sept. 2021.

Tesla shares also helped boost indexes as shares in

the electric carmaker gained after it said it would soon

increase the price of its Model Y EVs in parts of Europe.

Nvidia ( NVDA ) shares advanced but pared earlier gains. The

artificial intelligence poster-child kicked off its annual

developer conference, with investors waiting for new chip

announcements from Chief Executive Jensen Huang after the close.

Investors were torn between enthusiasm about the prospects

for AI on the technology sector and worries ahead to the Federal

Reserve's statement and commentary on Wednesday according to

Lindsey Bell, chief strategist at 248 Ventures in Charlotte,

North Carolina.

"This is a market that really wants to hold onto the

momentum trade but what's really weighing on investors' minds is

what happens with the Fed this week," said Bell.

"The market is sitting comfortably with the first cut coming

in June or July but not entirely confident it'll be the case.

The question is if it gets pushed out further."

According to preliminary data, the S&P 500

gained 32.48 points, or 0.63%, to end at 5,149.57 points,

while the Nasdaq Composite gained 130.28 points, or

0.82%, to 16,103.46. The Dow Jones Industrial Average

rose 73.44 points, or 0.19%, to 38,788.21.

Stronger-than-expected inflation figures have prompted

traders to rethink when and by how much policymakers will lower

rates this year, with traders pulling back the probability for a

June rate cut to around 51% from about 71% just a week ago,

according to the CME FedWatch Tool.

If the Fed were to take a hawkish tone when its policy

meeting concludes on Wednesday, this could pressure stocks.

"The fact we're up today provides investors with an

opportunity to take profits ahead of the Fed which is more

likely to disappoint than to support the recent rally in risk

assets," said Sameer Samana, Senior Global Market Strategist at

Wells Fargo Investment Institute in Charlotte.

Goldman Sachs on Monday said they now expect three interest

rate cuts in 2024, compared with four expected earlier, after

inflation came in a bit firmer than expected.

"With the market near recent highs its very difficult to see

what could provide an upside spark from here. It's not hard to

imagine the things that could cause disappointment," said Samana

citing the Fed and high valuations for tech stocks.

Exchange operator Nasdaq said it resolved an issue

related to connectivity and stock orders that had affected early

trading for more than two hours on Monday.

U.S.-listed shares of Xpeng climbed on its plans to

launch a cheaper EV brand amid fierce price competition.

Boeing ( BA ) fell after a media report that a federal grand

jury in Seattle issued a subpoena to the planemaker over the

Jan. 5 midair blowout of a Boeing ( BA ) door plug on an Alaska

Airlines flight.

Super Micro Computer ( SMCI ), which joined the S&P 500 on

Monday, gave up earlier gains. However, the stock, which has

been boosted by bets it would benefit from AI, is still up

sharply for the year-to-date.