No indication of Kroger's plans was given yesterday, and he could not be reached for comment.
His resignation raises new speculation about who will succeed the 61-year- old Blumenthal as chairman. Blumenthal has said on several occasions that he would like to retire before he reaches 65.
In a prepared statement, Blumenthal thanked Kroger for his "major contributions to the creation of Unisys," which was formed 15 months ago when Burroughs Corp. acquired Sperry Corp. Kroger had been president and chief operating officer of Sperry; Blumenthal and Stern both came from Burroughs.
Both Kroger and Stern served on the four-man executive group that oversaw the merger of the two companies, together with Blumenthal and executive vice president James A. Unruh.
Blumenthal abolished the group in August in favor of a seven-member management board on which Kroger's responsibilities seemed more vague than they had previously. Stern never had a position on the seven-member board
because he resigned.
Before August, Kroger had been in charge of all sales and marketing; in August he was assigned to "assist the chairman in the oversight of company affairs."
At the time, securities analysts said the restructuring was a move by Blumenthal to consolidate his power at the expense of Kroger and Stern.
"It is obvious that there is no one who is to be viewed as the senior executive of the company other than Mike Blumenthal," analyst Stephen Dube of Shearson Lehman Bros. said in August.
Kroger, 53, has spent more than half his life with Unisys and Sperry Corp. He joined Sperry as a sales representative in 1960 and moved through the ranks to become president and chief operating officer of Sperry in 1985.