Sources say Japan's government will sell shares in Tokyo's main subway network to the public in the year starting April 1.
The Ministry of Finance will market part of its 53 percent Tokyo Metro stake in an initial public offering to raise money for reconstruction after the 2011 earthquake and tsunami in northeastern Japan.
The exact timing of the deal is still being determined.
The Tokyo Metropolitan Government holds the remaining shares and will include some of them in the offering.
The local and national governments are expected to hold about half the company after the transaction.
They plan to eventually dispose their entire stakes.
A transport ministry panel recommended three years ago that the governments retain half of their holdings to support the subway operator's plan to expand its network.