* S&P 500 less than 1 percent from record levels
* 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 0.9 pct; Nasdaq up 1.7 pct (Updates to late afternoon)
By Caroline Valetkevitch
NEW YORK, May 12 U.S. stocks rallied on Monday, with the Dow hitting a record high and the S&P 500 within striking distance of its own record, while shares of Internet and biotech shares jumped.
Internet and biotech names were among the strongest advancers of the day. Biogen Idec gained 4.7 percent to $300.12 while TripAdvisor Inc shot up 6.4 percent to $90.02.
Both groups - often described as "momentum" stocks due to massive gains in recent months - have been wildly volatile in recent sessions, moving on concerns over valuation and hopes for high levels of growth.
The day's advance was broad, with S&P cyclical sector indexes such as materials, industrials and consumer discretionary all up more than 1 percent.
The rally came despite a vote by pro-Russian rebels in favor of self-rule in eastern regions of the country in a referendum dismissed by Kiev and Western governments as illegal. The European Union is set to step up pressure on Russia by taking steps to extend sanctions to companies, as well as individuals.
"The vote seemed like a negative, but the violence that many thought would happen didn't, and at this point, no news is good news when it comes to Ukraine," said Channing Smith, co-portfolio manager of the Capital Advisors Growth Fund at Capital Advisors in Tulsa, Oklahoma.
The Dow Jones industrial average rose 113.43 points or 0.68 percent, to 16,696.77, the S&P 500 gained 17.29 points or 0.92 percent, to 1,895.77 and the Nasdaq Composite added 70.61 points or 1.73 percent, to 4,142.482.
The Russell 2000 index of small-cap stocks climbed 2.5 percent. Last week, it flirted with correction territory, dropping nearly 10 percent from its all-time closing high.
Hillshire Brands Co agreed to buy Pinnacle Foods Inc in a deal valued at about $6.6 billion, including debt. Pinnacle jumped 12.3 percent to $34.20 while Hillshire fell 4.9 percent to $35.14. (Additional reporting by Ryan Vlastelica; Editing by Bernadette Baum and Jan Paschal)