The S&P 500 opened higher by 4.04 points, or 0.15 per cent, at 2,787.34.
Britain's exit from the European Union hung in the balance on Tuesday after Attorney General Geoffrey Cox said last-minute legally binding assurances won by Prime Minister Theresa May to her divorce deal left the legal risk over the Irish backstop unchanged.
The S&P and Nasdaq futures edged higher on Monday after inflation data showed US consumer prices in February rose for the first time in four months, but Boeing's fall for a second straight session pressured the Dow futures.
A report showing that USA consumer prices rose modestly last month - the latest evidence that inflation remains in check - also helped lift stocks.
The Dow Jones Industrial index fell on Monday as shares of the world's largest planemaker tumbled after a second deadly crash in just five months, but a jump in technology stocks helped cap some losses and lift the broader markets.
Traders appeared to mostly shrug off the developments in Britain, though US indexes lost some of their gains toward the end of the day as the Brexit vote was being held.
Stocks are opening mostly higher on Wall Street, led by gains in technology companies and banks.
Investors are still waiting for more details on any potential trade deal between the US and China.
The British pound saw volatile trade throughout the session, while the ICE U.S. Dollar Index, a measure of the U.S. currency against six major rivals, was down 0.3%.
U.S. stocks rose on Tuesday as benign February inflation data supported the Federal Reserve's dovish stance on future rate hikes, but Boeing's fall for a second straight session pressured the Dow. A key sales figure fell 2.2 percent in the period, worse than what analysts were expecting. Microsoft added 1.1 per cent and UnitedHealth Group climbed 2.6 per cent. The euro advanced to $1.1256 from $1.1245.
Bullion prices ended higher at Comex on Tuesday, 12 March 2019.
Ontario to ban cellphones from classrooms
Most, if not all, schools and school boards already have cellphone and technology related policies in place. The Ontario government will be banning cellphones in classrooms starting in the next school year.
Several dead in Brazil school shooting
Inside the school, police officials found a handgun and bottles that appeared to be Molotov cocktails, known as bottle bombs. Joao Doria, speaking a few blocks from the public school in Suzano, a suburb of Sao Paulo , Brazil's largest city.
Facebook, Instagram and WhatsApp down across the world
"We're aware that some people are now having trouble accessing the Facebook family of apps", the spokesperson said. Facebook is experiencing the worst outage in its history, with essential services left unusable for global users.
Retail inflation seen rising, industrial growth may soften
Gas prices for U.S. drivers were $2.31 a gallon on average in February, up from $2.25 in January, according to the U.S. The core PCE price index increased 1.9 per cent on a year-on-year basis in December after a similar gain in November.