(Reuters) - India's second-largest software services exporter Infosys Ltd beat forecasts and maintained its sales growth outlook for the year, citing strong demand from clients in its largest market the United States.

Many analysts had expected the company, which makes more than two-thirds of its sales from clients in the United States and Europe, to marginally cut its forecast of 7-9 percent sales growth for the year ending in March 2015 due to currency fluctuations.

Infosys kept the outlook after it posted a higher-than-expected 13 percent increase in net profit for the quarter ended December 31 on improved demand for outsourcing services.

Shares in Bengaluru-based Infosys extended their gains to as much as 6.9 percent after the results, while the Nifty was up nearly 0.1 percent.

Infosys has been losing market share and battling high staff attrition rate in the last few quarters as it struggled to compete with more nimble rivals.

Chief Executive Vishal Sikka was brought in last year to chart a new strategy for a company that was once a trendsetter for India's more than $100 billion IT outsourcing industry, by focusing on innovation and high-margin services including artificial intelligence and automation.

Infosys said staff attrition had slowed and client numbers increased during the third-quarter.

The company, which provides IT services to clients including Apple Inc, Wal-mart Stores and Volkswagen, posted a quarterly profit of 32.50 billion Indian rupees ($520.9 million), up from 28.75 billion rupees in the same year-ago quarter.

It also won 59 new clients, helping it boost its revenue in the period by 5.9 percent to 137.96 billion rupees.