Allison began his career at Merrill Lynch as an associate in investment banking and served variously as treasurer, director of human resources, chief financial officer, executive vice president, president, chief operating officer and as a member of the board during his 28 years there. While at Merrill Lynch, he worked in New York, London, Paris, and Tehran. After the stock market crash of 1987, Allison revised the bonus structure at Merrill Lynch, adding compensation based on company performance to a plan that was previously based on individual performance alone. "Herbies," as the options became known, were controversial at first but ended up being extremely successful both for the company and the individuals involved. In 1998, Allison played an instrumental role in preventing the collapse of Long Term Capital Management, a hedge fund whose rapid downturn in September of that year threatened the stability of the financial system. Allison proposed the solution that ultimately was adopted by fourteen Wall Street institutions. The participating institutions were all paid back. After leaving Merrill Lynch in mid-1999, he served as National Finance Chair for U.S. Senator John McCain's first Presidential Campaign. From 2000 to 2002, Allison was president and chief executive officer of the Alliance for Lifelong Learning, Inc., which offered online, college-level courses to adults. In 2002, Allison was named chairman, president, and chief executive officer of TIAA, a Fortune 100financial services organization that is the leading retirement provider for people who work in the academic, research, medical, and cultural fields. During his tenure, assets under management at the firm increased from $264 billion to over $435 billion. The company underwent significant change under his leadership, broadening its product lines beyond pensions to include financial services, life insurance, college savings plans, mutual funds, IRAs, and other offerings. The company also re-focused on customer service, adding offices closer to campuses, for example. Allison retired from TIAA in 2008, and was succeeded by Roger W. Ferguson, Jr.. Allison resigned as assistant secretary for financial stability in September 2010. Timothy Massad, who had been chief counsel to the Office of Financial Stability, succeeded him. Allison was a member of several boards and advisory councils, including Time Warner, Yale School of Management, Stanford Graduate School of Business, and the International Advisory Committee of the Federal Reserve Bank of New York. From 2003 to 2005 he was a director of the New York Stock Exchange. Allison died on July 14, 2013, at his home in Westport, Connecticut of a possible heart attack. He was 69.