I was surprised to read about NYSE Euronext halting trades on ING yesterday.

More than 99 million shares in the biggest Dutch financial- services company changed hands before a computer problem halted the stock at 4:30 p.m. in Amsterdam, according to data compiled by Bloomberg. Volume was almost six times the daily average for the last six months, the data show.

And

The malfunction is the latest to affect Euronext this year. Its owner, NYSE Euronext, had to delay the start of trading on its stock markets in Paris, Amsterdam, Brussels and Lisbon by about 45 minutes on April 20 because of a technical problem with the new trading system.