Formerly known as WorldCom, now known as MCI, this U.S.-based telecommunications company was at one time the second-largest long distance phone company in the U.S. Today, it is perhaps best known for a massive accounting scandal that led to the company filing for bankruptcy protection in 2002. WorldCom executives effectively fudged the company's accounting numbers, inflating the company's assets by around $12 billion dollars. The swift bankruptcy that followed led to massive losses for investors.

WorldCom's bankruptcy filing in 2002 was the largest such filing in U.S. history. The WorldCom scandal is regarded as one of the worst corporate crimes in history, and several former executives involved in the fraud faced criminal charges for their involvement. Most notably, company founder and former CEO Bernard Ebbers was sentenced to 25 years in prison, and former CFO Scott Sullivan received a five-year jail sentence, which would have been longer had he not pleaded guilty and testified against Ebbers. Under the bankruptcy reorganization agreement, the company paid $750 million to the Securities & Exchange Commission in cash and stock in the new MCI, which was intended to be paid to wronged investors.