This excerpt taken from the PBR 20-F filed May 22, 2009.
SFAS No. 159
In February 2007, the FASB issued Statement No. 159, The Fair Value Option for Financial Assets and Financial Liabilities (SFAS 159), which permits the measurement of certain financial instruments at fair value. Entities may choose to measure eligible items at fair value at specified election dates, reporting unrealized gains and losses on such items in earnings at each subsequent reporting period. We adopted this Statement effective January 1, 2008, but did not make a fair value election at that time or during the remainder of 2008 for any financial instruments not already carried at fair value in accordance with other accounting standards. Accordingly, the adoption of SFAS 159 did not impact our consolidated financial statements.