SIFMA provides comments to the Securities and Exchange Commission (SEC) on a proposed order approving a proposal by NYSE Arca, Inc. to establish fees for certain market data, Release No. 34-57917. Previously, NYSE Arca made the data available without charge. In a letter to the SEC on July 10, 2008, SIFMA provided qualitative and quantitative analysis showing that Nasdaq and NYSE/NYSE Arca each has the ability to exert monopoly pricing power and that they are using such power to charge fees that are not determined by competitive forces. NASDAQ submitted a rebuttal to this letter on September 10, 2008. This comment letter addresses NASDAQ’s criticisms and erroneous conclusions.