The firm engaged in prime brokerage and broker-dealer activities and was headquartered in New York City, occupying the entire 34 stories of 250 Vesey Street.

The company agreed to be acquired by Bank of America on September 14, 2008, at the height of the Financial crisis of 2007–2008, the same weekend that Lehman Brothers was allowed to fail.

Michael G. Ricciardi served as the head of the private equity funds group at Merrill Lynch & Co.[4][5] In 1921, the company purchased Pathé Exchange, which later became RKO Pictures.

On December 31, 1957, The New York Times referred to that name as "a sonorous bit of Americana" and said "After sixteen years of popularizing [it], Merrill Lynch, Pierce, Fenner, and Beane is going to change it—and thereby honor the man who has been largely responsible for making the name of a brokerage house part of an American saga," said about Winthrop H. Smith, who had been running the company since 1940.

The merger made the company – Merrill Lynch, Pierce, Fenner & Smith Inc. – the largest securities firm in the world, with offices in over 98 cities and membership on 28 exchanges.

[15] The brokerage also had partners in Canada interested in the retail investment business for a number of years, until selling this subsidiary to CIBC Wood Gundy in 1990.

In a report to the Finance Ministry, the Merrill Lynch group said it had acquired a 7.54 percent stake in TMS by purchasing some 3.33 million shares.

[19] Merrill Lynch rose to prominence on the strength of its network of 15,000 financial advisors, sometimes referred to as the "thundering herd", that allowed it to place securities it underwrote directly.

[20] In contrast, many established Wall Street firms, such as Morgan Stanley, relied on groups of independent brokers for placement of the securities they underwrote.

In 1978, it significantly buttressed its securities underwriting business by acquiring White Weld & Co., a small but prestigious old-line investment bank.

In November 2007, Merrill Lynch announced it would write-down $8.4 billion in losses associated with the subprime mortgage crisis, and would remove E. Stanley O'Neal as its chief executive.

[23] In his first days at work in December 2007, Thain made changes in Merrill Lynch's top management, announcing that he would bring in former New York Stock Exchange (NYSE) colleagues such as Nelson Chai as CFO and Margaret D. Tutwiler as head of communications.

[26] In July 2008, Thain announced $4.9 billion fourth quarter losses for the company from defaults and bad investments in the ongoing mortgage crisis.

[27] Two weeks later, the company announced the sale of select hedge funds and securities in an effort to reduce their exposure to mortgage related investments.

[29] Andrew Cuomo, New York Attorney General, threatened to sue Merrill Lynch in August 2008 over its misrepresentation of the risk on mortgage-backed securities.

[30] Three days later, the company froze hiring and revealed that it had charged almost $30 billion in losses to its subsidiary in the United Kingdom, exempting them from taxes in that country.

[31] On August 22, 2008, CEO John Thain announced an agreement with the Massachusetts Secretary of the Commonwealth to buy back all auction-rate securities from customers with less than $100 million in deposits with the firm, beginning in October 2008 and expanding in January 2009.

[33] Bloomberg reported in September 2008 that Merrill Lynch had lost $51.8 billion on mortgage-backed securities as part of the subprime mortgage crisis.

[35] To provide a ready supply of mortgages for the CDOs, Merrill purchased First Franklin Financial Corp., one of the largest subprime lenders in the country, in December 2006.

However, in 2010 Justice Bernard Fried disallowed all but one of the charges: the claim by MBIA that Merrill had committed breach of contract by promising the CDOs were worthy of an AAA rating when, it alleges, in reality they were not.

[43][44][45][46] Significant losses were attributed to the drop in value of its large and unhedged mortgage portfolio in the form of collateralized debt obligations.

Trading partners' loss of confidence in Merrill Lynch's solvency and ability to refinance short-term debt ultimately led to its sale.

The CEO at that time, David Komansky, said, "I want ... to publicly apologize to our clients, our shareholders, and our employees," for the company falling short of its professional standards in research.

Equal Employment Opportunity Commission (EEOC) brought suit against Merrill Lynch,[60] alleging the firm discriminated against Dr. Majid Borumand because of his Iranian nationality and Islamic religion, with "reckless disregard" for his protected civil rights.

[66] As of June 5, 2008, Merrill Lynch has created the West Asian, Middle Eastern and North African (WAMENA) Professional Network to help support and provide additional resources for employees of diverse backgrounds.

[67] New Jersey appeals court on August 13, 2008, rendered a ruling against Merrill Lynch in a discrimination lawsuit filed by a gay employee.

[68] In 2002 Merrill Lynch settled for a $10 million civil penalty as a result of improper activities that took place out of the firm's Fort Lee New Jersey office.

Merrill Lynch failed to reasonably supervise these financial advisers, whose market timing siphoned short-term profits out of mutual funds and harmed long-term investors.