This excerpt taken from the NYX 10-K filed May 1, 2007.
Fixed Income Business
The NYSE also operates a centralized bond market. A broad selection of bonds are traded on the NYSE, such as corporate (including convertibles), agency and government bonds. The trading volume of bonds on the NYSE is primarily in corporate bonds, with approximately 94% of this volume in non-convertible bonds. Bonds trade on the NYSE through NYSE BondsSM, a screen-based system launched in April 2007 used by NYSE member organization subscribers. NYSE BondsSM maintains and displays priced bond orders and matches those orders on a strict price and time-priority basis. It also reports real-time bids and offers with size and trades to our network of market data vendors.
On November 16, 2006, the SEC approved an exemption that allows NYSE members and member organizations to trade on an unlisted basis non-convertible corporate bonds issued by NYSE-listed equity issuers and their wholly owned subsidiaries. This will allow trading in approximately 5,000 bonds, compared to the approximately 820 bonds currently listed on the NYSE. The NYSE will be adding approximately 2,800 active corporate bonds that meet this SEC exemption over the next few months during Phase I of this initiative.