By Victor Reklaitis and Mark DeCambre, MarketWatch

Social-media heavyweight's shares decline more than 3%

U.S. stock benchmarks traded firmly lower Monday morning, with Facebook Inc. shares leading the downtrend as the social-media giant drew criticism over its management of user data.

Meanwhile, the Federal Reserve's coming policy decision also could be helping to undercut demand for equities.

Check out MarketWatch's Need to Know column: Why the case for betting against Facebook is 'building fast' (http://www.marketwatch.com/story/the-drumbeat-of-worries-around-facebook-and-other-tech-leaders-just-got-louder-2018-03-19)

What are the main benchmarks doing?

Dow Jones Industrial Average futures fell by 212 points, or 0.8%, to 24,743, while S&P 500 index shed 20 points, or 0.7%, to 2,731. The Nasdaq Composite Index lost 78 points, or 1.1%, to 7,402.

Last week, the Dow (http://www.marketwatch.com/story/us-stock-futures-struggle-as-political-worries-return-to-haunt-investors-2018-03-16) , S&P 500 and Nasdaq all declined by 1% or more, though each gauge erased part of its weekly loss by inching up Friday.

The Dow has pared its 2018 gain to 0.4%, while the S&P is up 2.4% for the year and the Nasdaq has advanced 7.4%.

What's driving markets?

Shares in Facebook (FB) shed 4.7% in premarket trading for the biggest drop among all stocks in the S&P 500 and Nasdaq-100. Facebook isn't part of the Dow industrials.

The Silicon Valley company has ignited a firestorm (http://www.marketwatch.com/story/facebook-sparks-international-furor-over-third-party-access-to-user-data-2018-03-18) over how it manages third-party access to its users' information, after saying a firm with ties to the 2016 Trump campaign improperly kept member data for years despite saying it had destroyed those records.

See:Web's creator blasts Facebook, saying it makes his invention easy to 'weaponize' (http://www.marketwatch.com/story/webs-creator-blasts-the-tech-giants-that-make-his-invention-easy-to-weaponize-2018-03-12)

The Federal Reserve has the attention of markets world-wide, with an interest-rate hike expected on Wednesday following a two-day meeting of the central bank's policy group, the Federal Open Market Committee. Higher interest rates can make riskier assets such as stocks less attractive.

Check out:The Fed is hogging the attention, but don't forget this critical number (http://www.marketwatch.com/story/the-fed-is-hogging-the-attention-but-dont-forget-this-critical-number-for-the-economy-2018-03-17)

Investors also have been worrying this month about a potential global trade war. The trade concerns come as the Trump administration takes a hawkish stance on U.S. trade with China and moves ahead with tariffs on foreign steel and aluminum (http://www.marketwatch.com/story/us-trade-groups-urge-trump-to-halt-tariff-plans-2018-03-18).

Read: U.S. soybeans would be China's biggest weapon in a trade war (http://www.marketwatch.com/story/us-soybeans-would-be-chinas-biggest-weapon-in-trade-war-2018-03-17)

And see:Trump's most market-rattling trade blasts are still to come, warns Pimco (http://www.marketwatch.com/story/trumps-most-market-rattling-trade-blasts-are-still-to-come-warns-pimco-2018-03-16)

There are no Fed speeches and no top-tier U.S. economic reports expected on Monday.

Which stocks are in focus?

KLA-Tencor Corp. (KLAC) said Monday it plans to acquire (http://www.marketwatch.com/story/kla-tencor-to-acquire-orbotech-in-deal-with-equity-value-of-about-34-billion-2018-03-19) Israeli electronics technology company Orbotech Ltd. (ORBK) in a deal with valued at about $3.4 billion and an enterprise value of about $3.2 billion. KLA-Tencor shares were down 1.7%, while those for Orbotech were up 6.9%.

Toronto-based cannabis company Cronos Group Inc.'s shares (CRON.V)climbed 6.1% Monday (http://www.marketwatch.com/story/cannabis-company-cronos-group-enters-cross-border-joint-venture-with-medmen-2018-03-19), after the company said it has entered a cross-border joint venture with MM Enterprises USA LLC, or MedMen Enterprises, to develop branded products and open stores across Canada.

What are strategists saying?

"The market is pricing in a 97.9% likelihood of a rate hike at this meeting. The big question then will be the 'dot plot' giving the FOMC members' estimates of where rates will be at the end of this year and next," said Marshall Gittler, chief strategist at ACLS Global, in a note.

"I expect that the committee will indeed revise up their forecast for rates, for next year if not for this year, and that this will boost the dollar."

Read more: What to expect from the new Fed dot plot on interest rates (http://www.marketwatch.com/story/what-to-expect-from-the-new-fed-dot-plot-on-interest-rates-2018-03-16)

And see:It's time for stock-market investors to refocus on the Fed (http://www.marketwatch.com/story/now-its-time-for-the-stock-market-to-refocus-on-the-fed-2018-03-16)

What other stocks are in focus?

Apple Inc.(AAPL) is reportedly designing and making its own display screens (http://www.marketwatch.com/story/apple-is-making-its-own-display-screens-for-the-first-time-bloomberg-2018-03-19) for the first time. The iPhone maker's shares fell 1.1% in premarket action.

Check out:This surging stock looks like a promising bet on electric cars--and it's not Tesla (http://www.marketwatch.com/story/this-surging-stock-looks-like-a-promising-bet-on-electric-cars-and-its-not-tesla-2018-03-17)

What are other markets doing?

European stocks (http://www.marketwatch.com/story/european-stocks-build-on-losses-as-micro-focus-shares-plunge-2018-03-19) lost ground, while Asian markets finished mixed (http://www.marketwatch.com/story/nikkei-leads-asian-market-declines-to-start-the-week-2018-03-18), with Japan's Nikkei benchmark down 0.9% as Prime Minister Shinzo Abe faced mounting pressure over a land-sale scandal.

March Madness:It's official--all brackets have been busted (http://www.marketwatch.com/story/its-official-all-the-march-madness-brackets-have-been-busted-2018-03-18)

And see:Live scores and win probabilities of every NCAA Tournament game (http://www.marketwatch.com/story/live-scores-and-win-probabilties-of-every-ncaa-tournament-game-2018-03-15)

Oil futures and the ICE U.S. Dollar Index fell, while gold futures also dipped.

(END) Dow Jones Newswires

March 19, 2018 09:47 ET (13:47 GMT)

Copyright (c) 2018 Dow Jones & Company, Inc.