NYSE said in a statement that "trading has resumed in those symbols at 1:17 p.m. ET (1717 GMT) and all systems are now operating normally."

A trading unit hosting 199 symbols failed, and orders on those symbols were being directed to other exchanges. Nasdaq (>> Nasdaq Inc) and Bats Global Markets declared "self-help" against the NYSE, which occurs when another exchange is dealing with internal problems processing trades and orders are routed through alternate venues.

"Orders just get routed to the exchanges where they can trade," said Ken Polcari, director of the NYSE floor division at O’Neil Securities from the floor of the NYSE.

Market-on-close and limit-on-close orders were canceled and will have to be submitted again, the NYSE said.

The NYSE initially announced the issue at 9:47 a.m. EDT (1347 GMT). Affected stocks included Jones Lang LaSalle Inc (>> Jones Lang LaSalle Inc), C. R. Bard (>> C R Bard Inc) and Taubman Centers Inc (>> Taubman Centers, Inc.).

The bug that affected the primary unit infected the backup, so after having said at 10:09 a.m. EDT (1409 GMT) that all systems were operating normally, the NYSE had to send another disruption alert at 10:26 a.m. EDT (1426 GMT).

Intercontinental Exchange (>> Intercontinental Exchange Inc) is the owner of the NYSE.

(Reporting by Chuck Mikolajczak, additional reporting by Rodrigo Campos; Editing by Nick Zieminski and Alan Crosby)

By Chuck Mikolajczak