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* Tech stocks gains as Apple hits record high, Alphabet rises
* Alphabet, Amazon jump as Morgan Stanley lifts price targets
* Canada, U.S. resume NAFTA talks amid growing optimism
* Dick's Sporting falls on weak sales, weighs on Under Armour
* Indexes up: Dow 0.31 pct, S&P 0.57 pct, Nasdaq 0.86 pct (Changes comments, updates to early afternoon)
By Shreyashi Sanyal
Aug 29 (Reuters) - U.S. stocks rallied on Wednesday, with the S&P 500 and Nasdaq hitting all-time highs for the fourth session in a row, boosted by a jump in Amazon.com and Alphabet, and on optimism over trade talks between the United States and Canada.
Morgan Stanley raised its price targets on Amazon and Google-parent Alphabet to become the most bullish Wall Street brokerage on the high-flying stocks and causing their shares to rise 2.7 percent and 1.5 percent, respectively.
The technology sector rose 0.88 percent, the most among the 11 major S&P sectors, as Alphabet gained. Apple hit a record high and was last up 0.9 percent.
The consumer discretionary index jumped 1.02 percent, as Amazon's gains more than offset a drop in retailers. Amazon's stock hit a record high and moved closer to following Apple into the $1 trillion market cap club.
"We're definitely seeing some of the previous market leaders heading the markets today," said Brant Houston, managing director of CIBC Private Wealth Management in Denver, Colorado.
"It's definitely a risk-on environment and investors are clearly bullish with some of the advancement in trade negotiations along with strong economic growth numbers."
There were signs that Ottawa was open to taking a more conciliatory approach in talks with Washington to salvage the North American Free Trade Agreement, after the U.S. and Mexico struck a deal on Monday.
U.S. economic growth was a bit stronger than initially thought in the second quarter, notching its best performance in nearly four years, Commerce Department data showed, as businesses spent more on software and imports fell.
At 12:48 a.m. ET the Dow Jones Industrial Average was up 80.93 points, or 0.31 percent, at 26,144.95, the S&P 500 was up 16.44 points, or 0.57 percent, at 2,913.96 and the Nasdaq Composite was up 68.92 points, or 0.86 percent, at 8,098.95.
Among other leading sectors were materials and energy which added 0.89 percent and 0.85 percent, respectively, as metal and oil prices rose.
Sportswear retailer Dick's Sporting fell 3.6 percent on weak sales that it partly blamed on low demand for products from Under Armour, pushing its shares down 0.7 percent.
American Eagle Outfitters slid 6.5 percent after missing profit estimates due to higher wages and advertising to support the expansion of its popular Aerie line of lingerie.
Apparel retailers and department store chains led the decliners on the S&P, but the S&P retail index was up 1.33 percent on Amazon's strength.
Advancing issues outnumbered decliners for a 2.07-to-1 ratio on the NYSE and a 1.63-to-1 ratio on the Nasdaq.
The S&P index recorded 57 new 52-week highs and one new low, while the Nasdaq recorded 96 new highs and 14 new lows. (Reporting by Shreyashi Sanyal in Bengaluru; Editing by Shounak Dasgupta)