The unannounced plan, outlined in company documents viewed by The Wall Street Journal, would replace thousands of workers at IBM facilities in Southbury, Conn., Poughkeepsie, N.Y., Raleigh, N.C., Dallas, Boulder, Colo., and elsewhere in the U.S. Already, the managers have been told, IBM has hired 500 engineers in India to take on some of the work that will be moved.

IBM calls its plan, first presented internally to some midlevel managers in October, "Global Sourcing." It involves people in its Application Management Services group, a part of IBM's giant global-services operations, which comprise more than half IBM's 315,000 employees.