The fourth-quarter loss worked out to $1.87 per share. Excluding special items the loss would have been 58 cents per share, matching expectations of analysts surveyed by FactSet.
A year ago the company lost $138 million, or 42 cents per share.
Revenue fell 2.5 percent to $8.7 billion.
Over the past year, United's financial performance has been consistently worse than its main competitor, Delta Air Lines Inc. Delta routinely posts larger monthly gains in passenger revenue, and on Tuesday it posted a 2012 profit of $1billion.
United, meanwhile, lost $723 million for the year, almost wiping out its $840 million profit from 2011. Revenue for the full year ticked up slightly to $37.15 billion.
It said first-quarter flying capacity would fall as much as 5.1 percent compared to a year ago. For the full year it plans to cut flying by a half-percent.
Wall Street prizes what it calls "capacity discipline" because fewer seats mean airlines can charge more for the ones that it makes available to passengers.
"We see improvement this year and expect UAL to narrow the gap between itself and peers on revenue performance," S&P Capital IQ analyst Jim Corridore wrote in a note.
But he added that the company's "ongoing integration challenges keep us cautious on the shares, despite our positive view on the overall U.S. airline industry."
United shares rose 54 cents, or 2.1 percent, to close at $25.54, after setting a new 52-week high of $26.36 earlier. The shares have gained about 25 percent since Dec. 1 amid a strong rally in airline stocks.