SIFMA provides comments to the Securities and Exchange Commission (SEC) on the Plan to Address Extraordinary Market Volatility Submitted to the Securities and Exchange Commission Pursuant to Rule 608 of Regulation NMS Under the Securities Exchange Act of 1934, by various self-regulatory organizations, File No. 4-631.  SIFMA agrees that there is a need to consider measures to limit destabilizing price moves in the financial markets, as noted in a previous letter dated October 12, 2010 to the Commodity Futures Trading Commission (CFTC) and SEC for the Joint CFTC-SEC Advisory Committee request for comments on preventing price swings in markets due to liquidity gaps.  SIFMA believes that the proposed limit up-limit down and trading pause pilot measures should help prevent extreme price swings and stock price dislocations that are caused by oversized marketable orders sweeping displayed liquidity to price levels not reasonably related to the value of the security.