This excerpt taken from the PBR 20-F filed May 22, 2009.
Taxation of Dividends
Dividends paid by us, including stock dividends and other dividends paid in property to the depositary in respect of the ADSs, or to a non-Brazilian holder in respect of the preferred or common shares, are currently not subject to withholding tax in Brazil.
We must pay to our shareholders (including holders of common or preferred shares or ADSs) interest on the amount of dividends payable to them, at the SELIC rate, from the end of each fiscal year through the date of effective payment of those dividends. These interest payments are considered as fixed-yield income and are subject to withholding income tax at varying rates depending on the length of period of interest accrual. The tax rate ranges from 15%, in case of interest accrued for a period greater than 720 days, to 22.5%, in case of interest accrued for a period up to 180 days. However, holders of ADSs and holders of common or preferred shares not resident or domiciled in tax haven jurisdictions investing under Resolution No. 2,689 are subject to such withholding tax at a reduced rate, currently at 15%. See Beneficiaries Residing or Domiciled in Tax Havens or Low Tax Jurisdictions.