Updates before markets open

By Shashwat Chauhan and Twesha Dikshit

Feb 19 (Reuters) - Wall Street's main indexes were set for a lower open on Thursday, following a three-day winning streak for the S&P 500, as heavyweight technology stocks slipped, while Walmart shares see-sawed after the retail giant issued a conservative outlook.

The retailer's WMT.O new CEO, John Furner, kicked off his tenure with a fiscal 2027 forecast that fell short of analyst expectations. Shares of the company were last up 0.5% in volatile premarket trading.

Other megacap and growth stocks, including Apple AAPL.O, Nvidia NVDA.O and Meta Platforms META.O, traded lower after rising in the previous session.

All three main U.S. indexes ended higher on Wednesday, as heavyweights including Nvidia and Amazon.com AMZN.O and other technology-related stocks, rose following recent jitters surrounding artificial intelligence.

Broader AI-linked and megacap technology stocks faced turbulence earlier this month amid concerns over high valuations and limited evidence that significant investments in AI were driving revenue and profit growth.

Sectors ranging from software to trucking were also hit by mounting concerns that rapidly improving AI tools could disrupt their business models.

Kim Forrest, founder and chief investment officer at Bokeh Capital, attributed the recent volatility in U.S. stocks to shifting sentiment towards AI.

"So on any given day, the bias switches very fast and that's a great indicator of overall investor nervousness."

At 8:47 a.m. ET, Dow E-minis YMcv1 fell 158 points, or 0.32%, S&P 500 E-minis EScv1 shed 21.5 points, or 0.31%, and Nasdaq 100 E-minis NQcv1 lost 99 points, or 0.4%.

In earnings-related moves, DoorDash DASH.O climbed 8.1% after the food delivery company forecast first-quarter marketplace gross order value above Wall Street estimates.

EBay EBAY.O rose 6.5% after the company forecast first-quarter revenue above analysts' estimates and announced the acquisition of fashion marketplace Depop from Etsy ETSY.N.

Carvana CVNA.O dropped 7% after the online used-car retailer missed fourth-quarter profit estimates on higher costs, while software provider EPAM Systems EPAM.N shed 20.5% after its cautious first-quarter outlook disappointed investors.

In other stocks, Hims & Hers HIMS.N shares added 2.4% after the telehealth firm said it would acquire Australian digital health company Eucalyptus for up to $1.15 billion.

Exxon Mobil XOM.N and Chevron CVX.N climbed over 1% each as crude oil prices rose on mounting fears of a military conflict between the United States and Iran.

Occidental Petroleum OXY.N climbed 5.4% after the U.S. shale producer beat fourth-quarter profit expectations.

WHAT THE FED THINKS

Meanwhile, minutes from the U.S. Federal Reserve's most recent policy meeting released on Wednesday showed policymakers were in near-unanimous agreement to hold interest rates steady.

Policymakers, however, remained split about the policy path later this year, with "several" open to rate hikes if inflation remains elevated, while others were inclined to support further cuts if it recedes in line with expectations.

At least four central bank officials, including Chicago Fed President Austan Goolsbee and Fed Vice Chair for Supervision Michelle Bowman, are scheduled to speak during the day.

The Personal Consumption Expenditure report - the Fed's preferred inflation gauge - is due on Friday.

(Reporting by Shashwat Chauhan and Twesha Dikshit in Bengaluru; Editing by Pooja Desai and Shinjini Ganguli)

((Shashwat.Chauhan@thomsonreuters.com;))