In a statement Nyse says Cormack and his family plan to relocate to Vancouver, Canada. He will step down from his current position in early 2007 but will continue as a senior consultant to Nyse.

Cormack joined Nyse following the exchange's takeover of Archipelago earlier this year. As well as being responsible for Arca trading operations and new product development at the US exchange, Cormack also oversees planning and acquisitions, such as Nyse's recent Matchpoint Trading and Marco Polo Network transactions.

Cormack joined Archipelago in January 2000 as national sales manager and was appointed president of the Archipelago Exchange (ArcaEx) in August 2000.

Prior to Archipelago Cormack was manager of equity trading at American Century Investments.

Cormack's day-to-day responsibilities at Nyse will be assumed by SVP Paul Adcock, who will become EVP, operations, Nyse Arca. Adcock, who is also one of the original Archipelago employees, currently manages Nyse Arca trade support efforts for equities, options and OTCBB.

In a separate move Marianne Brown, CEO of Securities Industry Automation Corporation (SIAC) is stepping down to join an undisclosed company.

SIAC - which is two-thirds owned by Nyse and one-third owned by the American Stock Exchange - is a technology centre that runs the computer systems and communications networks that power the two exchanges and disseminates market data.

Brown joined SIAC as CEO in February 2005 from ADP Brokerage Services Group where she held various positions of increasing responsibility encompassing sales, product development and technology operations and development.

Following her departure SIAC chairman and co-chief operating officer Jerry Putnam will become interim CEO.

Thomas Demcheck, senior vice president, will become chief operating officer.