(In last paragraph, corrects to show that percentage figure for Brazil revenue is for the full year)
By Christine Murray
MEXICO CITY, Feb 9 (Reuters) - Carlos Slim's America Movil on Tuesday reported a five-fold increase in quarterly profit, helped by a smaller loss from currency fluctuations, but tougher regulations in Mexico continued to squeeze margins at home.
The most important currencies to its business, Mexico's peso and Brazil's real, fell only slightly against the dollar in the fourth quarter, unlike in the third when exchange rate woes pushed America Movil to its first loss in 14 years.
Its exchange rate loss was 3.1 billion pesos in October-December, compared to a 22.8 billion peso loss in the prior year period, allowing net profit to beat analysts' expectations.
However, operating profit at Latin America's largest wireless and pay TV provider fell. Grappling with tough regulation at home and deepening recession in Brazil, America Movil's share price slipped more than 15 percent in the last year.
For the full year, the company's net profit fell 24 percent.
In its biggest market Mexico, America Movil is feeling the effects of a sweeping regulatory reform that has pushed down telecoms prices and squeezed the company's profit margin.
In the fourth quarter its Mexico earnings before interest, tax, depreciation and amortization (EBITDA) margin hit 36.7 percent, down from 42.6 percent a year earlier.
In March, telecoms regulator IFT will review the measures currently in place against the company.
America Movil said on Tuesday competition in Mexico was "very intense" with rivals such as Telefonica and AT&T .
The telecoms company, which is controlled by the family of billionaire Slim, posted a fourth quarter net profit of 15.7 billion pesos ($910 million), compared with 3.1 billion pesos a year earlier, beating expectations of a 13.0 billion peso net profit in a Reuters poll.
In its second-largest market Brazil, the company blamed a 1.2 percent drop in revenue on the weak economy. It disconnected some 4.9 million wireless subscribers, but continued to add customers in its larger fixed-line business.
Sales rose slightly to around 230.6 billion pesos, with revenue in Mexico just down. For the full year, revenue in Brazil rose 1.8 percent. ($1 = 17.2120 pesos at end-December) (Reporting by Christine Murray; editing by Dan Grebler and Andrew Hay)