OMG. This is by far the most expensive typo in history...

A Taiwan stock trader mistakenly bought $251 million worth of shares with a misstroke of her computer keyboard, meaning her company is looking at a paper loss of more than $12 million and she is looking for a new job.

The trader with Fubon Securities miskeyed in a small order from Merrill Lynch on Monday, creating confusion when many small companies inexplicably surged past the 7 percent trading limit. "Something like this is difficult to explain to superiors," a Fubon executive said Tuesday.

Fubon said that the trader was unfamiliar with new computer systems and will be fired. The company will also examine its procedures of placing orders, it said.