Khaleda Zia and Sheikh Hasina Wajed, who was arrested and detained over extortion allegations Monday, have each been asked to provide the information within a week, said Anti-Corruption Commission secretary Mukhlesur Rahman.
The two women, who lead the country's two main political parties, governed Bangladesh alternately between 1991 and 2006.
"Under the law, they have to submit the statements within seven working days. Else they may face legal actions," Rahman added.
The commission earlier this year served similar legal notices on dozens of leading politicians, some of whom have been jailed by special fast-track courts for failing to submit their statements.
Others have been convicted of corruption and jailed for up to 13 years.
The legal notices were served just a day after the country's military-backed government arrested Sheikh Hasina, leader of the Awami League, and a court summoned Zia, who leads the Bangladesh Nationalist Party (BNP) to appear before August 26 on tax evasi