The Securities and Exchange Commission has approved a rule change proposed by the International Securities Exchange (ISE) to decrease the minimum increment for entry and execution of single-sided, block-size orders through ISE’s Block Mechanism. Prior to the rule change, the Block Mechanism accepted and executed orders in standard increments of 5 and 10 cents and at split prices of 2.5 cents and 5 cents. Under the amended rule, orders may be entered and executed in penny increments using the Block Mechanism, but such orders will no longer be executed at split prices.

http://a257.g.akamaitech.net/7/257/2422/01jan20071800/edocket.access.gpo.gov/2007/pdf/E7-8597.pdf