* Indexes down: Dow 29 pts, S&P 4.75 pts, Nasdaq 11.25 pts
By Yashaswini Swamynathan
June 14 (Reuters) - U.S. stock index futures were lower for the fourth straight day as investors braced for the Federal Reserve's policy meeting and a referendum on Britain's European Union membership.
* The Federal Open Market Committee (FOMC) will commence its two-day meeting on Tuesday to decide whether the U.S. economy has recovered enough to be able to absorb an interest rate hike.
* While traders have discounted a hike this month, they will parse Fed Chair Janet Yellen's speech at a conference on Wednesday for clues on the health of the economy and the timing of the next hike.
* Yellen, who had been dropping hints last month of a rate hike in the near term, toned down her comments after a dismal May employment report set off fresh concerns of the strength of the economy.
* Traders have priced in a 17.9 percent chance of a rate hike next month and a 29 percent chance in September, according to CME Group's FedWatch tool.
* Oil prices extended losses as investors remained nervous over the rising possibility of Britain exiting the European Union when it votes on June 23.
* Recent opinion polls have indicated growing support for Brexit, adding to investor concerns.
* Reduced appetite for risky assets across the globe sent the yield on the 10-year German bond below zero for the first time ever.
* Investors will also keep an eye on U.S. retail sales data, which is expected to have risen 0.3 percent in May from a 1.3 percent rise the previous month. The data is expected at 8:30 a.m. ET (1230 GMT)
* Wall Street closed lower for the third straight session on Monday, dragged down by tech giants Microsoft and Apple .
* Chinese search engine company Baidu fell 6 percent to $153.74 premarket after lowering its current-quarter revenue forecast.
* Valeant rose 4.7 percent after CEO Joseph Papa purchased 202,000 shares.
* Twitter rose 2.7 percent to $14.95 after Goldman Sachs added the micro-blogging site to its list of companies that could be bought in the next year.
Futures snapshot at 7:11 a.m. EDT:
* Dow e-minis were down 29 points, or 0.16 percent, with 8,199 contracts changing hands.
* S&P 500 e-minis were down 4.75 points, or 0.23 percent, with 196,050 contracts traded.
* Nasdaq 100 e-minis were down 11.25 points, or 0.25 percent, on volume of 4,813 contracts. (Reporting by Yashaswini Swamynathan in Bengaluru; Editing by Don Sebastian)