* Dow and S&P 500 coming off record closing highs
* AT&T in talks to buy DirecTV: sources
* April retail sales data on tap, seen rising 0.4 pct
* Futures up: Dow 20 pts, S&P 2.9 pts, Nasdaq 3.75 pts
By Ryan Vlastelica
NEW YORK, May 13 (Reuters) - U.S. stock index futures were little changed on Tuesday as investors found few reasons to keep pushing shares higher following a sharp rally in the previous session that took the Dow and S&P 500 to record closes.
* Gains this year have come on improving signs of domestic growth, though traders continue to worry about the pace of economic expansion as well as tensions between Ukraine and Russia, which many fear could escalate into further violence.
* Insight into the state of the economy will come at 8:30 a.m. EDT (1230 GMT), when April data on both retail sales and import and export prices will be released. Sales are seen rising 0.4 percent in the month, which represents a deceleration from March, while import and export prices are both seen up 0.3 percent.
* Market participants are also watching merger activity. Late Monday, sources told Reuters that AT&T Inc was in active talks to buy DirecTV, and that it may complete a deal in the next few weeks that could be worth close to $50 billion. Shares of DirecTV rose 4.9 percent to $91.44 in premarket trading.
* Separately, Pfizer suggested it could raise its proposed $106 billion offer if AstraZeneca engaged in talks, as its boss was grilled by UK lawmakers on his commitment to British research spending and jobs. U.S. shares of Astra rose 0.7 percent to $78.39 before the bell.
* S&P 500 futures rose 2.9 points and were above fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures added 20 points and Nasdaq 100 futures rose 3.75 points.
* Wall Street rallied on Monday, with the S&P climbing 1 percent and the Nasdaq adding nearly 2 percent on the back of outperformance in the Internet and biotech space. The Russell 2000 index of small-cap stocks climbed 2.4 percent, its biggest daily percentage gain since early March.
* Russia said new European Union sanctions would hinder efforts to defuse the situation, urging the West to persuade Kiev to hold discussions on the country's future structure before a May 25 presidential election.
* China's economic activity showed across-the-board weakness in April, with economic indicators on investment and consumption missing expectations. The data sparked new calls for Beijing to ease policies to shore up growth. (Editing by Bernadette Baum)