 "Wall Street")
Wall Street opened slightly higher on Tuesday, minutes before Federal Reserve Chairperson Janet Yellen was scheduled to speak before the Senate Banking Committee on the monetary policy.
Yellen will also attend a meeting at 4:30 p.m. ET with other Fed officials.
"The markets like it when Janet Yellen speaks and in this case it looks like the weak May jobs number really spooked her. Investors are expecting her to be accommodative and allow the markets to inflate a little bit," said Keith Bliss, senior vice-president at Cuttone & Co in New York.
The central bank left interest rates unchanged last week and sounded caution after surprisingly weak monthly hiring data put the economy's recovery in question.
Wall Street, which rallied at the open on Monday, closed slightly higher as opinion polls showed fewer chances of Britain leaving the European Union.
Britain is scheduled to vote on Thursday, an event that has roiled the markets in the past week as investors fretted over its consequences, including the possibility of the EU falling apart if the country votes to leave.
Investors have erred on the side of caution in the past week, sticking to safe-haven assets such as gold and the yen.
Billionaire currency trader George Soros said a Brexit could trigger a more disruptive decline in the pound than on Black Wednesday when the government had to withdraw the currency from the European Exchange Rate Mechanism in 1992. Soros made billions betting against the currency that year.
The pound hit a 5-1/2 month high against the dollar, rising for the third straight session.
At 9:36 a.m. ET, the Dow Jones Industrial Average was up 14.18 points, or 0.08%, at 17,819.05.
The S&P 500 was up 2.63 points, or 0.13%, at 2,085.88.
The Nasdaq Composite was up 11.93 points, or 0.25%, at 4,849.14.
Six of the 10 major S&P sectors were higher, led by a 0.39% rise in the information technology index. Apple rose 0.5% and gave the biggest boost to the S&P and the Nasdaq.
Energy stocks were weighed down by a more than 2% fall in oil prices. Exxon fell 0.4% and was the biggest drag on the S&P.
Homebuilder Lennar rose 3.3% to $48.2 after reporting a better-than-expected quarterly profit.
American Science and Engineering rose 14.4% to $37 after OSI Systems said it would buy the company.
Advancing issues outnumbered decliners on the NYSE by 1,364 to 1,231. On the Nasdaq, 1,102 issues rose and 1,038 fell.
The S&P 500 index showed 3 new 52-week highs and no new lows, while the Nasdaq recorded 12 new highs and 6 new lows.
