Editing Sandler O'Neill and Partners (section)

===September 11 attacks===
On [[September 11 attacks|September 11, 2001]], the firm, which was headquartered on the 104th floor of the [[Two World Trade Center|South Tower]] of the [[World Trade Center (1973–2001)|World Trade Center]], lost 68 of its 171 employees, 40 percent of its overall workforce. One third of the firm's partners, almost the entire equity desk, the entire syndicate desk, and all of the firm's bond traders died during the attack.<ref name=sandfortpro/> Among those lost were Herman Sandler and Christopher Quackenbush, two of the three senior executives who managed the firm. [[Welles Crowther]], an equities trader for the firm now known as "The Man in the Red Bandana," also died during the attack. In addition to personnel, the company lost its entire computer system and nearly all of its records in the destruction.<ref name=sandlerprivatenyt />

On September 19, three days after the U.S. financial markets reopened, Dunne said on CNBC that Sandler O'Neill was open for business, having restarted operations as early as September 12.<ref name=sandfortpro>{{cite magazine|url=https://money.cnn.com/magazines/fortune/fortune_archive/2002/01/21/316599/index.htm|title=Starting Over When the planes slammed into the World Trade Center|last=Brooker|first=Katrina|date=21 January 2002|magazine=Fortune Magazine|access-date=30 June 2015|archive-date=14 September 2015|archive-url=https://web.archive.org/web/20150914215233/http://archive.fortune.com/magazines/fortune/fortune_archive/2002/01/21/316599/index.htm|url-status=live}}</ref> After the attacks, the firm operated temporarily out of the [[Solow Building]], in space provided by [[Bank of America]]. In early 2002, Sandler O'Neill moved from the Solow Building to [[919 Third Avenue]].<ref name=sandfortpro/> The firm remained in that building until another move in 2012.