U.S. stocks ended down slightly in a volatile session on Tuesday, led by a drop in materials and energy shares following further weakness in commodity prices.

Investors had hoped that the biggest U.S. banks would boost dividend payments substantially in 2015, but recent events including slumping oil prices will make it harder for banks to pay out more.

Brent and U.S. WTI crude oil prices fell to their lowest levels in almost six years on Tuesday as a big OPEC producer stood by the group's decision not to cut output to tackle a glut in the market.

A diplomatic push by Venezuela and Iran for an OPEC oil output cut has failed to soften the refusal of the group's Gulf members to do so for now, delegates said on Monday.

United Airlines is assessing whether to outsource jobs at airports around the country in a cost-cutting effort that could impact some 2,000 workers.

Huawei Technologies Co Ltd likely booked a 17 percent increase in operating profit last year, as worldwide adoption of fourth-generation (4G) mobile technology boosted earnings at China's leading telecommunications equipment maker.

The Twitter and YouTube accounts for the U.S. military command that oversees operations in the Middle East were hacked on Monday by people claiming to be sympathetic toward the Islamic State militant group being targeted in American bombing raids.

Germany's largest utility E.ON AG has agreed to sell its Italian gas- and coal-fired power plants to Czech energy company EPH, ridding itself of unwanted assets from an acquisition spree in 2007.

North Dakota oil producer Oasis Petroleum welcomes having hedge fund SPO Partners & Co as its largest shareholder, Chief Executive Tommy Nusz said in an interview on Monday, commenting on a fund that has been a shareholder since Oasis went public in 2010.

Malaysia's proposed $20 billion merger to create the world's biggest Islamic bank is likely to be scrapped after CIMB Holdings and RHB Capital failed to agree on new deal terms, people familiar with the matter told Reuters.