U.S. indices saw flat trading at midday Tuesday as optimism that the United Kingdom will remain part of the European Union was tempered by falling oil prices.
The S&P 500 and the Dow Jones industrials were each up about 0.1%, while the Nasdaq was down about 0.1%. Meanwhile, oil prices were down 2.1% in midday trading to $48.33, based on U.S. benchmark West Texas Intermediate.
Shares of United Continental (UAL) climbed about 3% after the airline increased its sales forecast for the second quarter, along with a new plan to boost its incremental value by $3.1 billion by 2018. United also said revenue per flown passenger mile will drop by 6.5% to 7.5% for the second quarter vs. previous guidance of up to 8.5%.
"With the renewed engagement of our 86,000 aviation professionals, a great global network, a highly flexible fleet plan and a healthy balance sheet -- all of the building blocks are in place for United to unlock its full potential," CEO Oscar Munoz said in a statement.
Meanwhile, shares of drugmaker Mallinckrodt (MNK) fell 3% as investors increasingly have been selling shares amid sentiment, most notably from short seller Andrew Left, that Mallinckrodt has hiked drug prices to unreasonable levels.
Auto parts maker BorgWarner (BWA) was down abut 4% after Bank of America analyst John Murphy published a forecast for 2016 U.S. auto sales of 17.7 million, down from a previous estimate of 18.2 million, while downgrading BorgWarner shares to Neutral from Buy.
-- Written by James Passeri