The U.S. economy expanded in the third quarter faster than previously estimated as consumers boosted spending on services such as health care and companies invested more in software. Gross domestic product (GDP) climbed at a 4.1 percent annualized rate, the strongest since the final three months of 2011 to beat an estimate of 3.6 percent, Commerce Department reported today. Inventories accounted for a third of the gain in GDP in the third quarter, showing companies were expecting increased demand. Stronger retail sales in October and November underscore the Federal Reserve???s view that the world???s largest economy is improving.