Jeff Bezos, 54, has a fortune that has soared as high as $160 billion (£125.3 billion) thanks to his stake in Amazon, which again became Wall Street's most valuable company this week, surpassing Microsoft Inc.
Bezos has credited MacKenzie, 48, for her support when he uprooted the young couple from New York to Seattle so he could launch the online bookseller that grew into one of the world's largest retailers. MacKenzie, a Princeton graduate who is now a novelist, did accounting for Amazon for its first year after it was founded in 1994.
The couple decided to divorce after a long period of "loving exploration" and trial separation, and expect to continue as partners in joint ventures and projects, according to the joint statement.
Reuters was unable to determine any further financial details of the planned divorce.