* Oil prices weaken for third straight day
* Charter to buy Bright Hose for about $10 bln
* Nasdaq set for longest-ever streak of quarterly gains
* Dow, S&P 500 and Nasdaq all fall 0.4 pct (Updates to market open, adds analyst comment)
By Ryan Vlastelica
NEW YORK, March 31 (Reuters) - U.S. stock fell on Tuesday in a modest retreat from the previous session's sharp rally, though major indexes remained on track for a positive first quarter and the S&P 500 was set for its ninth straight quarterly rise.
Energy shares will be in focus as crude oil fell 1.4 percent to $48 per barrel, sending the S&P Energy index down 1 percent and Exxon Mobil Corp down 1.1 percent to $84.73. Oil is set for its third straight daily decline, losing about 7 percent over that period.
Oil was pressured as Iran and six world powers entered a final day of talks on a nuclear deal that could see the energy-rich country increase oil exports. The talks come at a time when oversupply is already a major concern for energy investors, having contributed to crude falling more than 50 percent from a high in June.
Endurance Specialty Holdings Ltd agreed to buy reinsurer Montpelier Re Holdings Ltd for about $1.83 billion, while Charter Communications Inc agreed to acquire Bright House Networks in a roughly $10 billion deal.
The news follows a number of big deals announced on Monday, all of which contributed to the market's broad advance and the Dow's biggest one-day rise in more than a month. Charter rose 8.3 percent to $198.66 while Montpelier rose 3 percent to $39.31. Endurance fell 2 percent to $63.02.
"Today's move is largely in reaction to yesterday, a back-to-normal session, but our view on the market is still constructive. As we see continued acquisition deals, that will be supportive for the backdrop," said James Dunigan, chief investment officer at PNC Wealth Management in Philadelphia.
Trading may be volatile ahead of the March payroll report, due on Friday, when the stock market is closed for the Good Friday holiday. If the report is strong, investors could view the U.S. Federal Reserve as more likely to raise rates earlier than currently expected.
Tuesday marks the end of the first quarter. Over the period, the Dow rose 0.5 percent, the S&P 500 rose 0.9 percent and the Nasdaq rose 4 percent. This is the ninth straight quarterly advance for the S&P and Nasdaq, the longest such streak for the S&P since 1998 and the longest for the Nasdaq in its history.
The Dow Jones industrial average fell 74.74 points, or 0.42 percent, to 17,901.57, the S&P 500 lost 8.68 points, or 0.42 percent, to 2,077.56 and the Nasdaq Composite dropped 18.60 points, or 0.38 percent, to 4,928.84.
Declining issues outnumbered advancing ones on the NYSE by 2,028 to 628, for a 3.23-to-1 ratio; on the Nasdaq, 1,628 issues fell and 540 advanced, for a 3.01-to-1 ratio favoring decliners.
The S&P 500 was posting 6 new 52-week highs and no new lows; the Nasdaq Composite was recording 15 new highs and 10 new lows. (Editing by Nick Zieminski)