Alan Schein Photography/Corbis

A customer fuels his car at a gas station in Pembroke, Mass. Economists say Americans have been slow to spend the money they saved from lower energy prices. Stephan Savoia/AP hide caption

itoggle caption Stephan Savoia/AP

Aetna announced one of its largest pay hikes recently. CEO Mark Bertolini says he believes it largely could pay for itself by making workers more productive. Courtesy of Aetna hide caption

itoggle caption Courtesy of Aetna

Earlier this year, the European Central Bank, headed by Mario Draghi, launched a bond-buying program to drive down interest rates and boost borrowing. Emmanuel Dunand/AFP/Getty Images hide caption

itoggle caption Emmanuel Dunand/AFP/Getty Images

Depending on the amount taken in subsidies, or changes in reported income and family status, some Obamacare policyholders this year will get a bigger refund than expected and others will owe more in taxes. Carolyn Kaster/AP hide caption

itoggle caption Carolyn Kaster/AP

Supporters of the Affordable Care Act gather in front of the U.S Supreme Court during a rally Wednesday. The court heard arguments in the case and is expected to announce its decision in June. Alex Wong/Getty Images hide caption

itoggle caption Alex Wong/Getty Images

An oil well in Garden City, Texas. With prices plunging, oil companies are laying off thousands of workers. Spencer Platt/Getty Images hide caption

itoggle caption Spencer Platt/Getty Images