It gave no details. A spokesman said it would release a statement on the changes at 8.00 a.m. (0600 GMT) on Wednesday.
The current capital charge is 3 percent for Erste Bank unit Ceska Sporitelna and CSOB, owned by KBC ; 2.5 percent for Komercni Banka, majority-owned by Societe Generale ; and 1 percent for UniCredit Bank Czech Republic and Slovakia.
Komercni said after its second-quarter results that its rate would go up to 3.0 percent, the maximum possible charge. CSOB and Sporitelna expect their rates to remain at the maximum level.
It was not clear if a capital charge would be slapped on any additional banks apart from the largest four. All Czech banks are also subject to 0.5 percent capital charge to cover cyclical risks, and 2.5 percent capital conservation buffer.