This post is an example of human error in our highly technology dependent ecosystem. This sort of stuff is bound to happen now and then, but the key is to build systems that can prevent or at least minimize the effects of human error.
The screen shots below are from Yahoo Finance from June 13, 2007. For a few minutes, the SIMG ticker was displaying the stock price for SIGM. Although the matter was corrected in a few minutes, the consequences of human action from incorrect information can be extreme. In the second screen shot, while the stock price has been corrected, the system still shows an incorrect loss.