* Futures down: Dow 28 pts, S&P 4.25 pts, Nasdaq 7.5 pts
By Yashaswini Swamynathan
March 14 (Reuters) - U.S. stock index futures were marginally lower on Tuesday ahead of the Federal Reserve's closely watched two-day meeting, where it is widely expected to raise interest rates.
* Britain's parliament paved the way for Prime Minister Theresa May to launch divorce talks with the European Union, potentially adding a layer of uncertainty in the market.
* An almost certain U.S. rate hike lifted the dollar by a third of a percent to 101.67.
* Wall Street's major indexes have been trading in a tight range since the start of the month as investors prepared for higher rates following a slew of hawkish comments from top Fed officials.
* Stocks ended flat on Monday, with the S&P 500 trading in its tightest range this year as the focus was firmly fixed on the Fed meeting.
* The next big question for the market is whether the Fed could get on a more aggressive path to tightening monetary policy than previously expected as economic data shows signs of improvement, with a potential boost from President Donald Trump's proposed fiscal policies.
* The Fed will release a statement at 2:00 p.m. ET (1800 GMT) on Wednesday followed by a press conference by Fed Chair Janet Yellen.
* Shares of Valeant plunged 13 percent to $10.56 in heavy premarket trading after billionaire investor William Ackman said his hedge fund, Pershing Square Capital Management, sold its entire stake in the company.
* DSW was up 3.4 percent at $20.50 after the footwear and accessories maker reported quarterly profit that beat analysts' average estimate. Futures snapshot at 7:23 a.m. ET:
* Dow e-minis were down 28 points, or 0.13 percent, with 8,775 contracts changing hands.
* S&P 500 e-minis were down 4.25 points, or 0.18 percent, with 94,620 contracts traded.
* Nasdaq 100 e-minis were down 7.5 points, or 0.14 percent, on volume of 4,353 contracts. (Reporting by Yashaswini Swamynathan in Bengaluru; Editing by Anil D'Silva)