(Updates with details from report)
MEXICO CITY, Feb 2 (Reuters) - Mexico's America Movil suffered its largest loss in 15 years in the fourth quarter, as higher financial costs dragged on the giant telecoms company amid shrinking margins at home.
Latin America's biggest telecoms firm, which is controlled by the family of billionaire Carlos Slim, said the 5.972 billion peso ($289 million) net loss compared with a net profit of 15.663 billion pesos in the year-earlier quarter.
Financial costs in the period more than doubled to 29.639 billion pesos, America Movil said.
Between October and December, Mexico's peso was battered by Donald Trump's advance to victory in the U.S. presidential election, making dollar-denominated equipment more expensive.
The results also bucked expectations for a 5.337 billion peso profit in a Reuters poll of six analysts.
It was America Movil's second loss since the fourth quarter of 2001, and comes as the firm grapples with much tougher antitrust regulation and competition at home.
In the third quarter of 2015 the company posted a loss of 2.884 billion pesos.
In Mexico, where it competes with Telefonica SA and AT&T Inc, the company has almost 70 percent of wireless subscriptions but since 2014 has been subject to more stringent rules.
Its earnings in Mexico before interest, tax, depreciation and amortization (EBITDA) fell 23.6 percent, while the EBITDA margin shrunk for the tenth consecutive quarter.
Total revenue at America Movil, which operates across the Americas and in Europe via its Telekom Austria unit, grew by 16.9 percent to 269 billion pesos, beating expectations in the Reuters poll for a figure of 265 billion pesos.
In its second-largest market Brazil, ongoing economic weakness dragged EBITDA down 2.4 percent. At Telekom Austria EBITDA also fell in the quarter, down 17.7 percent.
Slim, who dined with Trump after his election victory, told Mexicans in January not to fear the real estate magnate, and praised the country's growing national unity.
$1 = 20.64 pesos at end of December Reporting by Christine Murray; Editing by Diane Craft and Lisa Shumaker