On September 18th, NYSE Euronext reminded members that September 21, 2012, is a quarterly Expiration Day for stock and index options and futures products whose settlement pricing is based upon New York Stock Exchange and NYSE MKT opening or closing prices on that day. Members should review Exchange rules and policies regarding opening imbalance publications, entry and cancellation of market-on-close/limit-on-close and closing offset orders, publication of on-the-close imbalances, and printing the closing transaction. NYSE Euronext Information Memo 12-22.