Observing that the H-1B work visa programme helps hire the best available talent of the world, American software giant Microsoft has said H-1B visa holders has contributed significantly to its success.

However, the company, which had recently announced to lay off some 5,000 jobs in the next 18 months, would be handing over pink slips to H-1B visa holders too.

Microsoft's observation on H-1B visas and their significant contribution to its success was made by the company in a letter to Senator Charles Grassley.

H-1B employees have always accounted for less than 15 per cent of Microsoft's US workforce, the level that is used in immigration law to determine whether a company is "H-1B dependent," the letter said.

The Senator, in a letter dated January 22, had sought information from Microsoft particularly about how its plan to fire 5,000 people would affect US workers and non-US citizens working for Microsoft.

The Microsoft letter dated March 3 written by Bradford L Smith, its general counsel, has been posted on its website http://microsoftontheissues.com.

"Nonetheless, the ability to tap into the world's best minds has long been essential to our success. Although they are a small percentage of our workforce, H-1B workers have long made crucial contributions to Microsoft's innovation successes and to our ability to help create jobs in this country.

"We are confident this will continue to be true in the future," said the Microsoft.

Microsoft said it focuses its recruiting for core technology jobs at US universities, which continue to be among the best in the world for computer science and engineering graduates.

However, as one recent study found, in 2005 temporary residents earned more than 40 per cent of the engineering and computer science degrees at US higher education institutions.

For doctoral degrees, that number was even higher, as temporary residents accounted for 59 per cent of the degrees awarded in these fields that year, the letter said.

"The substantial majority of H-1B petitions filed by Microsoft are for core technology positions, and technology and engineering positions account for about 90 per cent of Microsoft's H-1B workforce," Microsoft said.

Many of these H-1B employees have been seeking permanent resident status for many years and would no longer be dependent on their H-1B visas but for multi-year delays in the green card process, the letter observed.

"With these factors taken together, we do not expect to see a significant change in the proportion of H-1B employees in our workforce following the job reductions," said the company in its letter.

Answering to the specific question from the Senator on H-1B people losing their jobs, the Microsoft said: "Workers on H-1B visas and other temporary work visas make up only a small percentage of our overall workforce, but they were also among the employees impacted by the reductions announced in January.

Employees outside the United States were also impacted." Since majority of Microsoft's workforce is made up of US workers, the company said the majority of jobs eliminated in January were held by US workers.