Excess supply in the U.S. and very weak demand in Brazil have pressured profits for Brazil-based steel producer Gerdau and its U.S. subsidiary, Gerdau Ameristeel, while the depreciation of the Brazilian real weakened the company's leverage levels. We're revising the outlook to negative from stable and affirming our 'BBB-' global scale and 'brAAA' national scale ratings on the company. The negative outlook reflects our view that Gerdau's credit metrics will remain pressured at least until the end of 2016, which can result in a downgrade if we see further weakening of volumes and prices in Brazil along with supply demand imbalances in the U.S. SAO PAULO (Standard&Poor's) Jan. 21, 2016--Standard&Poor's Ratings Services revised its outlook on