* Dow ends best two-week period since June 2012
* For the week, Dow up 1.6 pct; S&P and Nasdaq each up 1.3 pct
* Twitter shares slide after massive rally
* Textron to buy Beechcraft for $1.4 billion in cash
* Dow off 0.01 pct, S&P 500 down 0.03 pct, Nasdaq down 0.3 pct
By Sam Forgione
NEW YORK, Dec 27 (Reuters) - U.S. stock indexes closed mostly flat on Friday, with the Dow snapping a six-day streak of record closing highs after investors took a break from this week's rally.
Shares of Twitter Inc, the social media company that has nearly tripled in value since going public in early November, slid 13 percent to close at $63.75 after investors took profits. Twitter was among the most actively traded stocks on the New York Stock Exchange on Friday.
The tech-heavy Nasdaq fell 0.25 percent, with leaders like Apple off 0.7 percent at $560.09 and Facebook Inc. down about 4 percent at $55.44. The Nasdaq has surged 37.7 percent this year, making it the best performer among the three major U.S. stock indexes.
"Consolidating a little bit here is probably healthy rather than continuing a march higher without taking a breath," said Joseph Benanti, managing director of Rosenblatt Securities in New York. "It's a healthy pause with some profit-taking."
Volume overall was light, as it has been all week. About 4 billion shares traded on U.S. exchanges, well below the average of about 6.1 billion this month, according to data from BATS Global Markets.
Both the Dow and the S&P 500 wrapped up a second straight week of solid gains. The S&P 500 posted its best two-week period since July, while the Dow marked its best two weeks since June 2012. The S&P 500 has soared 29.1 percent this year, on track for its best year since 1997. The Dow has climbed 25.8 percent this year, on track for its best year since 1996.
Sprint Corp shares jumped 8.3 percent to $10.79, following speculation that a deal by Japan's SoftBank Corp to acquire U.S. wireless carrier T-Mobile US is closer to getting done. Sprint's stock also hit a 52-week high at $11.46 in Friday's regular session.
The Dow Jones industrial average fell 1.47 points or 0.01 percent, to end at 16,478.41. The S&P 500 dipped just 0.62 of a point, or 0.03 percent, to finish at 1,841.40. The Nasdaq Composite dropped 10.59 points or 0.25 percent, to close at 4,156.59.
Friday's slight decline also halted the S&P 500's run of four record closing highs in a row.
For the holiday-shortened week, the Dow gained 1.6 percent, the S&P 500 added about 1.3 percent and the Nasdaq advanced about 1.3 percent. The U.S. stock market was closed on Wednesday for Christmas and trading had ended early on Tuesday.
In company news, Textron Inc agreed to buy aircraft maker Beechcraft Corp for $1.4 billion in cash. Textron shares rose 1.1 percent to close at $36.61.
General Motors Co's China joint venture will recall close to 1.5 million vehicles because of potential safety issues in one of the biggest recalls in the world's biggest auto market. GM's stock fell 1.4 percent to end at $40.94.
Advancers outnumbered decliners on the NYSE by a ratio of about 8 to 7. On the Nasdaq, about 13 stocks fell for every 12 that rose.