* Futures shrug off report of fall in weekly jobless claims
* Surge of holiday packages delays UPS shipments
* T-Mobile rises, sources say SoftBank in talks to buy
* Futures up: Dow 62 pts, S&P 2.5 pts, Nasdaq 6 pts
NEW YORK, Dec 26 (Reuters) - U.S. stock index futures pointed to slight gains at the open on Thursday, suggesting the market's upward movement will continue, although trading was expected to be light following the Christmas holiday.
Thursday is the first full day of trading since Monday, following an early close on Tuesday and Wednesday's Christmas holiday. Volume has been anemic, with many traders away.
The light action could amplify market volatility.
Nevertheless, markets showed an upward bias, with the Dow pointing to a sixth straight day of gains, its longest winning streak since March.
Both the Dow and S&P 500 closed at record highs on Tuesday. However, further upside may be limited at these levels, especially in the absence of major trading catalysts.
"There's nothing to drive markets decisively higher other than continued momentum, but I don't see that stopping. It has been a long time since we've had such an absence of headwinds," said Pete Benson, partner of Beacon Capital Management in Frankville, Tennessee.
In the latest economic data, initial jobless claims fell to the lowest level in nearly a month. The Labor Department said claims dropped by 42,000 to 338,000. Analysts had expected the level to be 345,000. The report had little impact on stock futures.
Stock movers may include United Parcel Service a day after the shipping company said poor weather and a high volume of holiday packages delayed the arrival of Christmas presents around the world.
Also, Amazon.com Inc offered compensation to affected customers with shipping refunds and $20 gift cards.
"There will be a lot more active trading on this space today, and it will be interesting to see how the negative talk on social media influences the stock," said Benson. "However, if this does turn out to be a big negative for shipping companies today, I think that will just be a blip."
S&P 500 futures rose 2.5 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 62 points and Nasdaq 100 futures rose 6 points.
The S&P 500 has soared 28.5 percent this year, largely due to stimulus measures from the U.S. Federal Reserve. The index is on track for its best year since 1997. The Dow is up 24.8 percent in 2013 while the Nasdaq has jumped 37.6 percent for the year.
Japan's SoftBank Corp was in talks to acquire U.S. wireless carrier T-Mobile US Inc and was discussing funding for a deal with financial institutions, sources close to the matter told Reuters. Shares of T-Mobile rose 3.4 percent to $33.30 in premarket trading.
In another black eye for the retail industry, the hackers who attacked Target Corp and compromised up to 40 million credit cards and debit cards also managed to steal encrypted personal identification numbers, a senior payments executive told Reuters.