Western Digital has a stake in the chip unit thanks to its SanDisk acquisition and says Toshiba can’t sell the unit without the stakeholder’s permission.
Toshiba rejected Western Digital's bid for the unit.
Earlier this week, Toshiba selected a Japan-backed consortium as the bid winner, but Western Digital vowed to keep up the legal fight.
The consortium has reportedly offered Western Digital a role, which Toshiba supports but refuses to become the first to say so on the record.
Western Digital shares are up 4.76%.
Previously: Reuters: Tech industry casts doubts on Toshiba’s lead chip unit bidder (June 22)
Subscribe for full text news in your inbox