US STOCKS-Futures dip, extending recent weakness, on rate uncertainty
* Indexes have fallen for two straight weeks
* Alcoa to buy RTI International for $1.5 bln
* GM up in premarket, to launch buyback program
* Futures down: Dow 23 pts, S&P 2.75 pts, Nasdaq 3.75 pts (Updates trading, adds Alcoa news)
By Ryan Vlastelica
NEW YORK, March 9 (Reuters) - U.S. stock index futures fell on Monday, continuing a recent downtrend on Wall Street as investors speculated over whether interest rates could be raised sooner than expected.
Major indexes slumped on Friday, with the S&P 500 suffering its biggest one-day loss in about two months, after the U.S. nonfarm payrolls report for February showed jobs growth that was much stronger than expected.
That was seen as possibly pressuring the Federal Reserve to act soon on monetary policy, as the central bank had said it would raise rates when the economy was strong enough to support it.
While a more robust economy is better for stocks in the long run, investors have been concerned that a rate rise too soon - which would raise borrowing costs for companies and individuals - could damp growth as the economy's recovery has been slow. Continuación...