* 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 0.6 pct; S&P 500 up 0.8 pct; Nasdaq up 1.5 pct (Updates to midday trading)
By Ryan Vlastelica
NEW YORK, May 12 U.S. stocks rallied on Monday, with cyclical names driving the Dow to its second all-time high in as many sessions as the S&P 500 moved within striking distance of its own record.
Gains were broad, with eight of the 10 primary S&P 500 sectors in positive territory. Cyclical groups such as materials and industrials ranked among the day's biggest gainers. The only sectors to decline were utilities and telecom, both considered defensive plays. About 77 percent of stocks traded on the New York Stock Exchange rose, while more than three-fourths of Nasdaq-listed stocks gained.
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.
Internet and biotech names were among the strongest advancers of the day so far. Biogen Idec gained 4 percent to $298.12 while TripAdvisor Inc shot up 6.5 percent to $90.07. Both sectors - 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 Dow Jones industrial average was up 99.98 points, or 0.60 percent, at 16,683.32. The Standard & Poor's 500 Index was up 15.33 points, or 0.82 percent, at 1,893.81. The Nasdaq Composite Index was up 62.69 points, or 1.54 percent, at 4,134.56.
The S&P 500 is 0.2 percent from a record intraday high reached on April 4. The Russell 2000 index of small-cap stocks rose 2.1 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 13.7 percent to $34.61 while Hillshire fell 6.4 percent to $34.60.
Tesaro Inc surged 18 percent to $28.33 after the company said its experimental drug to prevent chemotherapy-induced nausea and vomiting met the main goal in a third late-stage trial. (Editing by Bernadette Baum and Jan Paschal)