* Q3 adj EPS $0.36 vs est $0.54
* Q3 rev $1.75 bln vs est $1.77 bln
* Cuts FY rev est to $6.8 bln from $7.1 bln earlier
* Shares fall as much as 18 pct (Adds analyst comments, trading volume; updates share move)
Oct 27 (Reuters) - Wireless carrier NII Holdings Inc's third quarter missed estimates and cut full-year revenue outlook as it expects to be hit by lower exchange rates and increased competition in its Latin American market.
Shares of the company, which operates under the Nextel brand, were down 15 percent at $25.84 in afternoon trade. They touched a low of $25.03 in morning trade.
More than 11 million shares changed hands by 1412 ET, about four times their average volumes.
"Investors already knew about the impact from currency, but the information on increased competitive environment in Brazil is new," Mizuho Securities analyst Michael Nelson said.
Competitors like Telefonica Brasil SA could slow NII's growth rate in Brazil, he said.
NII now expects full-year revenue of $6.8 billion, down from its previous outlook of $7.1 billion.
Analysts on average were expecting full-year revenue of $6.93 billion, according to Thomson Reuters I/B/E/S.
The company expects increased competition in Brazil and lower currency exchange rates to continue to hurt its results for the full year.
For July-September, net loss was $2.9 million, or 2 cents a share, compared with a profit of $118.5 million, or 70 cents a share, a year ago.
Adjusted earnings for NII, which targets business customers in Mexico, Brazil, Argentina, Peru and Chile, was 36 cents a share, according to Thomson Reuters I/B/E/S.
Consolidated revenue for the quarter was $1.75 billion.
Analysts on average had expected earnings of 54 cents a share, before items, on revenue of $1.77 billion, for the quarter. (Reporting by Durba Ghosh in Bangalore; Editing by Gopakumar Warrier)