Among the companies listed on the letter are major Indian offshore firms, including Wipro Technologies and Tata America International Corp. -- a subsidiary of offshore giant Tata Consultancy Services -- as well as firms that rely heavily on India and other countries for offshore labor, including U.S.-based Cognizant Technology Solutions and Accenture.

Other firms signing it included eBay, EMC, General Electric, Hewlett-Packard Co., Intel, Microsoft, Texas Instruments, as well as a number of firms in other industries, including Boeing, Dow Chemical, Caterpillar and Chevron USA. The U.S. Chamber of Commerce, along with numerous tech-related groups, signed it, too.

The lobbying effort has been largely behind-the-scenes, but its goal was outlined in a letter released earlier this month by the two leading congressional critics of work visa policies, U.S. Sens. Richard Durbin (D-Ill.) and Charles Grassley (R-Iowa).

In their letter to U.S. Citizenship and Immigration Service (USCIS) Director Alejandro Mayorkas, Grassley and Durbin said they were aware that the agency was considering making it easier for companies to transfer workers to the U.S. under the L-1B rules. The L-1 is the visa most commonly used.

"We are concerned that the L-1B program is harming American workers because some employers, especially foreign outsourcing companies, use L-1B visas to evade restrictions on the H-1B visa program," wrote Grassley and Durbin.