Offshore outsourcing companies continued to make up the majority of the top 10 H-1B visa users in 2011, according to new government data. These offshore firms have been adding employees by the thousands as their revenues increase.

Wipro's IT services revenue grew 12 percent year on year in U.S. dollar terms in the quarter ended Dec. 31, but its growth lags behind Indian outsourcing peers such as Tata Consultancy Services (TCS).

India's National Association of Software and Service Companies (Nasscom) said Monday that an economic slump in the U.S. will benefit Indian outsourcers, as U.S. customers look to cut costs.

Wipro's second-quarter revenue grew, the company reported Wednesday. However, its larger competitors, Infosys and Tata Consultancy Services, grew faster.

Indian outsourcers have been typically known to develop enterprise software or offer IT services. But India's third largest outsourcer, Wipro, is taking advantage of having once designed and manufactured its own PCs and servers, to design and manufacture hardware products for customers.

The service quality at top Indian outsourcers is dropping as they scramble to hire staff to cope with an unexpected surge in demand, analysts said.

Clients of Indian outsourcers consider it critical to have access to, and to build a relationship with, the heads of these companies, according to a study by Offshore Insights, a research and advisory firm in Pune, India.

Wipro, India's third largest outsourcer, said on Wednesday that its IT services business had grown by 20 percent to US$1.4 billion for the quarter ended March 31, reflecting strong demand from outside the country for offshore services.