Opening Bell: Stocks Rise Ahead of Yellen Testimony; Boeing Signs Deal With Iran Air

U.S. stocks opened higher on Tuesday as investors await testimony from Federal Reserve Chair Janet Yellen and fears of a Brexit continue to fade. Billionaire investor George Soros warned of a currency crisis for the pound if the UK left the EU, similar to the one seen in the early 1990s, according to an op-ed in The Guardian. 'It won't be pretty for the pound - whether it's going to compare with the crisis in the 90s which Soros made his fame, perhaps not,' said Simon Smith, chief economist at FxPro, based in London. Meanwhile, Boeing shares (BA) - Get Report rose after signing an agreement with Iran Air, which intends to buy Boeing jetliners. This comes after burdensome sanctions were lifted following the landmark Iran nuclear deal from last year. TheStreet's Scott Gamm reports from Wall Street.