(CNN) Here's a look at Enron, an energy trading company that collapsed after a massive accounting fraud scheme was revealed. Its 2001 bankruptcy filing was the largest in American history at the time. Estimated losses totaled $74 billion.

Facts

An independent review published in 2002 detailed how executives pocketed millions of dollars from complex, off-the-books partnerships while reporting inflated profits to shareholders.

Timeline

1985 - Houston Natural Gas merges with Omaha-based InterNorth to form Enron.

1986 - Lay is appointed chairman and CEO of Enron.

1989 - Enron enters the natural gas commodities trading market.

1990 - Skilling, an energy consultant, is hired to run a new subsidiary called Enron Finance Corp.

February 12, 2001 - Skilling becomes CEO while Lay stays on as chairman.

August 14, 2001 - Skilling resigns and Lay becomes CEO again.

August 2001 - Sherron Watkins, a vice president, warns Lay that the company could "implode in a wave of accounting scandals."

October 16, 2001 - Enron announces a third-quarter loss of $618 million. The company later reveals that it overstated earnings dating back to 1997.

October 31, 2001 - The company discloses that it is under formal investigation by the Securities and Exchange Commission.

November 9, 2001 - Enron confirms that it has agreed to be purchased by a rival company, Dynegy for $9 billion.

November 28, 2001 - Dynegy announces it has terminated merger talks with Enron.

December 2, 2001 - Enron files for Chapter 11 bankruptcy protection.

January 10, 2002 - Arthur Andersen LLP, the accounting firm that handled Enron's audits, discloses that its employees had destroyed company documents.

January 15, 2002 - The New York Stock Exchange suspends trading of Enron shares.

January 17, 2002 - Enron ends its partnership with Arthur Andersen.

February 12, 2002 - Lay invokes his Fifth Amendment right before the Senate Commerce Committee.

July 5, 2006 - Lay dies of a heart attack while awaiting sentencing.

September 8, 2008 - The $7.2 billion settlement will be paid out by a group of banks accused of participating in the accounting fraud scheme. A class action lawsuit filed by shareholders and investors is settled in federal court. The $7.2 billion settlement will be paid out by a group of banks accused of participating in the accounting fraud scheme.

May 11, 2009 - Skilling files a petition with the Supreme Court to overturn his conviction after appeals with the lower courts fail.

May 9, 2010 - "Enron," a Broadway musical about the company's collapse, closes on Broadway 12 days after opening amid slow ticket sales.

December 8, 2015 - permanently barring him from serving as an officer or director of a publicly held company. The judgment settles a long-running civil suit by the SEC. The SEC announces that it has obtained a summary judgment against Skilling, permanently barring him from serving as an officer or director of a publicly held company. The judgment settles a long-running civil suit by the SEC.

February 21, 2019 - Skilling is released after serving over 12 years in federal prison.