The NYSE seemed to be having a major liquidity event today. Taking liquidity (market orders) was prohibited by 2:20 CT for the rest of the day and only limit orders (Providing liquidity) were allowed.
Here is the most recent.
02:59pm 12 Jun 09:
Market oddlot and PRLs in Matching Engine One (Update)
As a follow-up to today's issue with Matching Engine One, we have found that market oddlot orders and oddlot portions of partial roundlot orders (PRLs) are not executing in the affected symbols (listed below). However, oddlot orders and PRLs with limit prices are executing properly in these symbols. For the remainder of the day, customers should cancel unexecuted market oddlot orders and the oddlot portions of partial roundlot orders in the affected symbols, and submit only oddlot orders and PRLs with limit prices.