* Indexes: Dow up 0.38%, S&P 500 off 0.03%, Nasdaq slips

0.21%

* Investors await earnings from 'Mag 7' companies; chips

slide

* Airlines and cruise operators edge higher as oil declines

* Fed decision due on Wednesday

(Updates throughout)

By Johann M Cherian and Ragini Mathur

July 27 (Reuters) - Wall Street's main indexes were mixed on

Monday as investors remained wary of volatility in the Middle

East despite a U.S.-Iran de-escalation, while awaiting guidance

from major technology companies in what could prove to be a

"make-or-break" week.

Four of Wall Street's "Magnificent Seven" companies

Microsoft ( MSFT ), Amazon ( AMZN ), Meta and Apple ( AAPL )

are set to report earnings later in the week, which

will determine if the years-long AI rally has further room to

run.

Microsoft ( MSFT ) added 2.3%, Apple ( AAPL ) and Meta were up about 1%, while

Amazon ( AMZN ) was flat.

"This is a make-or-break week for technology," said

Christian Fromhertz, CEO at The Tribeca Trade Group.

"I'm more worried about this week than anything else because

if Microsoft ( MSFT ), Meta, and Amazon ( AMZN ) don't start telling investors

when they're going to be making money on all of this CapEx, then

there's a problem."

U.S. stocks ended a rough week on Friday after negative

cash-flow reports from Alphabet and Tesla

added to concerns about debt-fueled corporate spending.

Chinese chipmaker CXMT Corp's stellar debut on

Monday and a report that the country has started

manufacturing homegrown DUV chipmaking tools also signaled

intensifying competition for the U.S. semiconductor industry.

Tech stocks declined the most on the S&P 500,

slipping 1.4%, with chip stocks leading the slide. The

Philadelphia SE Semiconductor Index dropped 4% and was about 22%

below its June record high. Sandisk ( SNDK ) tanked 11%, Nvidia ( NVDA )

dropped 4.4% and Micron lost 4.7%.

On the flipside, communication services rose 2.3%

as Alphabet rebounded 3%.

At 12:42 p.m., the Dow Jones Industrial Average rose

197.41 points, or 0.38%, to 52,144.66, the S&P 500 lost

1.86 points, or 0.03%, to 7,410.12 and the Nasdaq Composite

shed 50.91 points, or 0.20%, to 24,924.91.

MIDEAST TRUCE SHAKY

Brent crude prices slid 7.4% to $89.63 a barrel on

relief that the recent spike in tensions between Iran and the

U.S. was temporarily on hold.

However, the ceasefire was fragile as shipping through the

Strait of Hormuz remained low and Iran's neighbors continued to

face fresh drone attacks, prompting a warning from President

Donald Trump that he is ready for "strong military action" if

talks fail, a report said.

A wide swathe of stocks sensitive to energy prices gained.

United Airlines and Delta Air Lines ( DAL ) edged up

about 1% each, as did cruise operators Royal Caribbean

and Carnival.

Oil companies Occidental Petroleum ( OXY ) and Exxon Mobil

were down about 2% and 1.2%, respectively.

The Fed's monetary policy decision is due on Wednesday and

investors expect rates to be left unchanged, but are pricing in

at least 25 basis points of increase later this year,

LSEG-compiled data showed.

The Personal Consumption Expenditures Price Index for June

is due a day after the central bank's decision and will be key

in shaping market expectations for interest rates later this

year.

Software stocks, which had been hit several times

earlier this year on AI-disruption worries, gained 2.8% with

Workday up 8.9%.

Advancing issues outnumbered decliners by a 1.66-to-1 ratio

on the NYSE and by a 1.63-to-1 ratio on the Nasdaq.

(Reporting by Johann M Cherian and Ragini Mathur in Bengaluru;

Editing by Saumyadeb Chakrabarty and Joyjeet Das)