The campaign's goal is to get $1 billion (euro690 million) in pledges over the next three years from companies that will give employee time to nonprofit groups. Organized by the President's Council on Service and Civic Participation, the campaign is designed to help nonprofits fulfill back-office services such as marketing, accounting, technology and management consulting.

More than 120 executives from the business and nonprofit worlds will join government officials, including Labor Secretary Elaine Chao, at the summit in New York.

So far organizers say they have received commitments from 18 companies such as General Electric Co., Target Corp., UPS, Citigroup Inc., Intel Corp., IBM Corp. and Accenture. They plan to announce eight pledges totaling almost $120 million on Wednesday.

Deloitte & Touche LLP, the accounting and consulting firm, will contribute $50 million (euro34.39 million) in pro bono consulting services over the next three years.

"The message to our people is, if you spend time doing this, it's just as important to us as the client side," said Brian Derksen, vice chairman and deputy chief executive at Deloitte.

"There are a lot of little guys that can't afford the skills a Deloitte would have," said Stephen Goldsmith, chairman of The Corporation for National and Community Service, a federal agency that runs programs such as AmeriCorps, and a professor at the Kennedy School of Government at Harvard University.

Companies are responding in part to surveys that show employees place a high value on being able to volunteer in a way that utilizes skills learned at work.

Younger workers and ready-to-retire workers rate volunteer opportunities high on a list of priorities when looking for an employer. Because of that, companies increasingly see volunteer programs as a corporate benefit they can use to recruit and retain the most desired employees.

Other pledges to be announced on Wednesday: IBM will contribute at least $6 million (euro4.1 million) over the next year and Intel will contribute at least $7.5 million (euro5.2 million) over the next year. The pledges were valued based on the number of employee hours and the company's usual rates for service.