Sandler O'Neill + Partners, L.P., (Sandler O'Neill) was a full-service investment banking firm and broker-dealer specializing in the financial services sector. It was headquartered in New York City, and had offices in Boston, Chicago, San Francisco and Atlanta. The firm also operated a mortgage finance company and registered investment adviser based in Memphis. Sandler O'Neill provided investment banking services to financial institutions and their investors. Its services include merger and acquisition advisory, capital markets, fixed income sales and trading, and equity sales and trading, equity research, balance sheet management, mortgage finance, and consulting services. The firm publishes research on about 300 financial institutions across the United States. Despite shifts in the way similar Wall Street firms are run, Sandler O'Neill retained its private partnership structure, and was the largest private investment bank dedicated to the financial sector. It ranked among the top advisers on bank and thrift mergers as well as in capital raising. In 2019, the company was acquired by Piper Jaffray and renamed Piper Sandler Companies. The combined company is headquartered in Minneapolis. History Sandler O'Neill + Partners, L.P. was founded in 1988 by Herman S. Sandler, Thomas O’Neill and four other executives from the firm Bear Stearns. Though today it serves companies of all sizes, the firm was founded with an emphasis on community and mid-size banks, as its founders saw that smaller financial institutions were underserved by the existing advisement system. Six months after the foundation of the firm, Christopher Quackenbush left Merrill Lynch to build Sandler's investment banking group. Two years after Sandler's establishment it formed Sandler O'Neill Mortgage Finance, an affiliate of Sandler O'Neill + Partners. The affiliate is currently headquartered in Memphis but maintains an office in New York City separate from the firm's headquarters. In 1993, the company moved to Two World Trade Center (South Tower) from Two Wall Street. The same year, Sandler O'Neill opened an equity sales and trading division. The following year, the firm began publishing equity research, focusing on community banks and other financial institutions. Sandler O'Neill had four satellite offices in addition to its main office in New York City. The first was opened in Boston in 1998. Offices in Atlanta and San Francisco were opened in 2003. A final satellite office was opened in 2004 in Chicago. The firm ranked among the best performing investment banking firms, advising financial firms on strategic and financial initiatives, including