Lehman Brothers Holdings Inc. () was a global financial services firm. Before filing for bankruptcy in 2008, Lehman was the fourth-largest investment bank in the United States (behind Goldman Sachs, Morgan Stanley, and Merrill Lynch), doing business in investment banking, equity and fixed-income sales and trading (especially U.S. Treasury securities), research, investment management, private equity, and private banking. Lehman was operational for 158 years from its founding in 1850 until 2008.On September 15, 2008, the firm filed for Chapter 11 bankruptcy protection following the massive exodus of most of its clients, drastic losses in its stock, and devaluation of assets by credit rating agencies, largely sparked by Lehman's involvement in the subprime mortgage crisis, and its exposure to less liquid assets. Lehman's bankruptcy filing is the largest in US history, and is thought to have played a major role in the unfolding of the late-2000s global financial crisis. The market collapse also gave support to the "Too Big To Fail" doctrine.After Lehman Brothers filed for bankruptcy, global markets immediately plummeted. The following day, Barclays announced its agreement to purchase, subject to regulatory approval, Lehman's North American investment-banking and trading divisions along with its New York headquarters building. On September 20, 2008, a revised version of that agreement was approved by U.S. Bankruptcy Judge James M. Peck. The next week, Nomura Holdings announced that it would acquire Lehman Brothers' franchise in the Asia-Pacific region, including Japan, Hong Kong and Australia, as well as Lehman Brothers' investment banking and equities businesses in Europe and the Middle East. The deal became effective on October 13, 2008.