US STOCKS-Dow, S&P 500 end at record highs; DirecTV up late
* DirecTV shares up after the bell on AT&T deal news
* Hillshire to buy Pinnacle Foods for $6.6 billion
* Ukraine situation remains in focus after referendum
* Dow up 0.7 pct; S&P 500 up 1 pct; Nasdaq up 1.8 pct (Updates close with DirecTV shares up after the bell, adds 21st Century Fox and latest volume)
By Caroline Valetkevitch
NEW YORK, May 12 (Reuters) - The Dow and the S&P 500 ended at record highs on Monday while the Nasdaq rallied as shares of Internet and biotech shares advanced.
Biogen Idec jumped 4.8 percent to $300.54 and TripAdvisor Inc rose 5.8 percent to $89.51. Twitter gained 5.9 percent to $33.94 after news reports that brokerage SunTrust raised its rating on the stock to "buy."
These momentum shares have been wildly volatile in recent sessions after a sharp selloff that began in March on concerns about their high valuations.
"I think it's stabilizing a little bit for those stocks. Some would say they're still overvalued, but they've come down enough that it doesn't seem they have that much further to fall. Now people are trying to pick up bargains, and some of those stocks have been going up," said Giri Cherukuri, head trader at OakBrook Investments LLC in Lisle, Illinois. Continuación...