US STOCKS-Rotation out of megacaps set to weigh on Nasdaq at open

* Pfizer up on lifting annual sales forecast for COVID-19
vaccine
* CVS Health higher on raising 2021 profit outlook
* Futures fall: Nasdaq 0.82%, Dow 0.40%, S&P 0.53%

(Adds details; Updates prices throughout)
By Shreyashi Sanyal
May 4 (Reuters) - The Nasdaq index was set to open lower on
Tuesday as investors continued to move out of megacap growth
stocks and into companies that are expected to benefit from the
reopening of economies.
Highly valued technology companies including Microsoft Corp
MSFT.O , Alphabet Inc GOOGL.O , Apple Inc AAPL.O , Amazon.com
Inc AMZN.O and Facebook Inc FB.O fell between 0.6% and 1.7%
in premarket trading.
U.S. and European stock markets also saw a sudden 0.5% drop
in hefty volumes around 7:30 a.m. ET on Tuesday, leaving traders
scratching their heads and one calling it a "micro flash crash".
Copious stimulus measures, speedy vaccination drives and the
Federal Reserve's accommodative policy stance have spurred a
strong rebound in the U.S. economy and pushed Wall Street to
record highs this year. The so-called "pandemic winners",
however, have recently started to fall out of favor.
"While megacap tech companies have been a core part of the
solid performance of portfolios throughout the pandemic, we
think investors should be careful to avoid overallocation to
this part of the market," Mark Haefele, chief investment officer
at UBS Global Wealth Management, wrote in a client note.
"In an environment of accelerating growth, we continue to
prefer cyclical and value sectors such as financials and
energy."
Planemaker Boeing Co BA.N rose 0.2%, while oil major
Chevron Corp CVX.N gained 0.7%.
At 8:38 a.m. ET, Dow e-minis 1YMcv1 were down 136 points,
or 0.4%, S&P 500 e-minis EScv1 were down 22.25 points, or
0.53%, and Nasdaq 100 e-minis NQcv1 were down 113 points, or
0.82%.
Among other stocks, Pfizer Inc PFE.N rose 1% as it raised
its annual sales forecast for the COVID-19 vaccine it
co-developed with Germany's BioNTech SE BNTX.O . CVS Health Corp CVS.N gained 1.7% on reporting
first-quarter profit above analysts' estimates and raising its
2021 profit forecast. Dupont DD.N edged 0.5% higher after the industrial
materials maker raised its full-year profit and revenue
forecasts and beat first-quarter expectations. First-quarter earnings have been largely upbeat. Average
profits at S&P 500 companies are expected to have risen 46% in
the quarter, compared with forecasts of a 24% growth at the
start of April, according to IBES data from Refinitiv.
Investors also awaited data through the week, including the
Labor Department's non-farm payrolls data, slated to be released
on Friday. The report is expected to show a rise in job
additions in April.