(Adds share buyback program)
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.
Two of the most important currencies to the company's 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.
The exchange rate loss was 3.1 billion pesos in October-December, compared with a 22.8 billion peso loss in the prior year period, helping net profit 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 Mexico, its biggest market, 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 Mexico earnings before interest, tax, depreciation and amortization 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 that competition in Mexico was "very intense" with rivals such as Telefonica and AT&T .
It also announced it would propose putting 12 billion pesos toward its share buyback fund, less than half of the 35 billion pesos shareholders approved in 2015.
The 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 Brazil, its second-largest market, 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 in the quarter, with revenue in Mexico just down. ($1 = 17.2120 pesos at end-December) (Reporting by Christine Murray; Editing by Dan Grebler, Andrew Hay and Leslie Adler)