The next trade 8 minutes later was for 15 contracts at 77 cents. The fund was the eighth-most traded ETF for the past month, data compiled by Bloomberg show. Robert Madden, a spokesman for Nasdaq, Gail Osten, of CBOE, and Suzanne O'Halloran at Bats Global Markets Inc, declined to comment. Molly McGregor at International Securities Exchange and John Nester, an SEC spokesman, didn't return phone calls and emails. Amex, a unit of NYSE Euronext, reported "systems issues" earlier and asked that orders from the platform be removed from marketwide price quotes, a system known as the national best bid and offer. Options venues run by Nasdaq, Bats and CBOE routed orders away the exchange. Amex said systems were back to normal by 9:49 am in New York.