Knight Capital(KCG), the financial services firm that triggered a trading glitch in August that cost it some $440 million, shut down trading Wednesday because of an electrical outage.
The news comes after a two-day closure of major U.S. stock markets due to Hurricane Sandy's drubbing of the East Coast.
Knight told clients in a memo that it was experiencing "power issues" and asked them to trade equities elsewhere, according to Bloomberg News.
"The SEC gets bashed a lot, but it made the right decision to coordinate the market closures," Robert Battalio, a finance professor at University of Notre Dame, wrote in an email about the two-day closure. "Closing the exchange means there were a lot of bad trades that didn't happen. ... Computers can't be programmed for every contingency; there is still a need for people to 'babysit' trading."