US STOCKS-Wall Street closes broadly higher on deal news, vaccine hopes

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* Nvidia climbs on $40 bln deal for chip designer Arm
* Pfizer, BioNTech expand late-stage COVID-19 vaccine trial
* Oracle surges on partnership with TikTok parent

(Updates to close)
By Caroline Valetkevitch
Sept 14 (Reuters) - U.S. stocks ended sharply higher on
Monday as signs of progress in developing a COVID-19 vaccine and
a spurt of multibillion-dollar deals lifted investor optimism.
Drugmaker AstraZeneca AZN.L resumed its British clinical
trials of its COVID-19 vaccine, one of the most advanced in
development. MKTS/GLOB
Also, Pfizer Inc PFE.N rose after the drugmaker and German
biotech firm BioNTech SE 22UAy.F proposed to expand their
Phase 3 pivotal COVID-19 vaccine trial to about 44,000
participants. "The market loves anything with a vaccine because that is
the ultimate solution here. And we'll see more and more
headlines," on that going forward, said Tim Ghriskey, chief
investment strategist at Inverness Counsel in New York, New
York.
Merger-related news also lifted the market, he said.
Nvidia Corp NVDA.O jumped on plans to buy UK-based chip
designer Arm from Japan's SoftBank Group Corp 9984.T for as
much as $40 billion, in a deal set to reshape the global
semiconductor landscape. The Philadelphia SE chip
index .SOX also rose.
Oracle ORCL.N gained as the cloud services company said
it would team up with China's ByteDance to keep TikTok operating
in the United States, beating Microsoft Corp MSFT.O in a deal
structured as a partnership rather than an outright sale.
U.S. stocks are coming off of two straight weeks of losses
as investors sold heavyweight technology shares that had powered
the benchmark index to record highs in a dramatic recovery from
its March lows.
Unofficially, the Dow Jones Industrial Average .DJI rose
321.54 points, or 1.16%, to 27,987.18, the S&P 500 .SPX gained
42.29 points, or 1.27%, to 3,383.26 and the Nasdaq Composite
.IXIC added 203.11 points, or 1.87%, to 11,056.65.
All of the S&P 500 sectors were higher, and tech heavyweight
Apple Inc AAPL.O gave the S&P 500 its biggest boost.
Tesla Inc's shares TSLA.O rebounded after losses last
week. Later this week, investors will focus on the Federal
Reserve's last policy meeting before the Nov. 3 U.S.
presidential elections.
In other deal news, Immunomedics Inc's shares IMMU.O
jumped after Gilead Sciences Inc 's GILD.O $21 billion buyout
deal, which is a steep premium to the biotech company's closing
price on Friday.