The chief whip of Chancellor Angela Merkel's Christian Democrats (CDU) and his counterpart with their Bavarian sister party CSU, Alexander Dobrindt, are to formally nominate him later Wednesday, the officials who spoke on condition of anonymity told AFP.
The sources said Schäuble, 75, was ready to accept the change to leave the ministry, where he has been a staunch backer of austerity for stricken eurozone member states. His unbending stance on Greece cast him as a villain in the struggle to save Athens from crashing out of the euro.
The general election on Sunday saw Merkel win a fourth term as German chancellor but without a ruling majority.
Her previous junior partners, the Social Democrats, said they would move to the opposition following a dismal result in the poll.
Merkel must now try to form a government likely to include the Free Democratic Party, which has already staked a claim to the powerful finance minister job.
Bild said Merkel personally asked Schäuble to become parliamentary speaker, arguing that the "job will have greater importance than usual given the arrival of the AfD in the Bundestag" lower house.
Schäuble, who has served in the Bundestag for 45 years, is a giant of the German political scene.
He will replace the highly respected Norbert Lammert, who retired at the end of the last parliamentary term this month.