(For a live blog on the U.S. stock market, click or type LIVE/ in an Eikon news window.)
* S&P, Dow hit record highs for second straight session
* Chevron, Exxon gain on higher oil prices
* Micron warns tariffs to impact results; Chipmakers slip
* Indexes: Dow 0.21 pct, S&P 0.12 pct, Nasdaq 0.26 pct (Adds comments, updates prices)
By Shreyashi Sanyal
Sept 21 (Reuters) - The S&P 500 and Dow Jones Industrial Average touched record highs for a second session running on Friday, helped by a boost for energy stocks from higher oil prices as changes to Wall Street industry sectors index spurred volatility.
Eight of the 11 major S&P sectors gained ground with the S&P energy sector rising 0.58 percent led by Chevron and Exxon Mobil as oil markets awaited a weekend meeting of OPEC.
Technology and consumer stocks, however, handed back an early burst of gains after the bell, with traders pointing to fallout from the biggest reshuffle since 1999 of Wall Street's broad industry sectors as a driving factor.
Telecoms major AT&T, set to form the heart of a new powerhouse communications sector that will now include Facebook , Google parent Alphabet and Twitter, rose 1.75 percent and was the biggest contributor to the S&P.
"We are seeing investors use the sector realignment as an excuse to take some profits from these high growth technology stocks," said Chad Oviatt, director of investment management at Huntington Private Bank in Columbus, Ohio.
At 11:00 a.m. ET the Dow Jones Industrial Average was up 57.00 points, or 0.21 percent, at 26,713.98, and the S&P 500 3.43 points, or 0.12 percent
With “quadruple witching” expirations and the S&P's quarterly rebalancing of its indexes also playing in, the tech-heavy Nasdaq dipped, with Apple and Amazon.com down 0.5 percent and 0.8 percent respectively.
Many of the companies that have powered the tech rally are being reclassified in the overhaul that takes effect on Monday and may demand a substantial reorganisation of holdings by big institutional investors.
Apple will remain in the tech sector, where it will account for 20 percent of the index's market capitalization while Amazon will again be classed as a consumer discretionary firm.
In the consumer sector, shares in McDonald's rose 2.0 percent after the company ended a week marked by strikes across the country over workplace sexual harassment by raising its quarterly dividend by 15 percent to $1.16.
A 4-percent drop in shares in Micron led chipmakers lower after the Idaho-based firm said U.S. tariffs on Chinese goods would weigh on its financial results for as much as a year.
In general, however, trade concerns have moved into the background since Tuesday's latest blows in the conflict with China, allowing the resumption of a rally that dates back a decade.
Advancing issues outnumbered decliners by a 1.25-to-1 ratio on the NYSE. Declining issues outnumbered advancers for a 1.36-to-1 ratio on the Nasdaq.
The S&P index recorded 51 new 52-week highs and no new lows, while the Nasdaq recorded 43 new highs and 18 new lows. (Reporting by Shreyashi Sanyal in Bengaluru; Editing by Sriraj Kalluvila and Shounak Dasgupta)