A week after joining Mayer Brown's New York office, capital markets partner James Tanenbaum has left the firm following allegations that he engaged in inappropriate conduct at Morrison & Foerster (MoFo).

Tanenbaum, who was part of a team of capital markets, corporate and securities lawyers that moved to Mayer Brown from MoFo in late February, tendered his resignation after reports surfaced that he had been terminated by MoFo in late 2017 in connection with an internal investigation into allegations of sexual misconduct. 

"Today, Mayer Brown accepted the resignation of James Tanenbaum, who recently joined the firm," the firm said in a statement. "His resignation follows assertions that Tanenbaum may have engaged in inappropriate conduct at his former firm. Tanenbaum has informed Mayer Brown that he forcefully denies these assertions, but that he has determined that resigning is in the best interest of Mayer Brown, its clients and the capital markets group. We wish Tanenbaum well."

Mayer Brown declined further comment about Tanenbaum's departure or when it became aware of the accusations against him. Tanenbaum himself did not return requests for comment about the allegations or his resignation.

According to Above the Law, which first reported the story, anonymous sources within MoFo said that Tanenbaum, who once led that firm's global capital markets practice, was accused of "sexual harassment" and "inappropriate behaviour". Tanenbaum was reportedly reprimanded two years ago by the firm after it was initially made aware of his behaviour.

However, after allegations resurfaced again last year, Above the Law noted that MoFo retained an independent outside firm to conduct an internal investigation into Tanenbaum's conduct.

A source told Above the Law that the day after the report was completed, Tanenbaum was asked to leave the firm. He officially left Morrison & Foerster in December 2017.

A MoFo spokesman declined to comment about Tanenbaum's departure from the firm or the allegations of sexual misconduct. Last month, a former associate at the firm, Terdema Ussery II, was accused of sexual misconduct during his time as president and CEO of the National Basketball Association's Dallas Mavericks. Ussery denied the allegations.

Tanenbaum joined MoFo's New York office in 2003 from US firm Stroock & Stroock & Lavan, alongside Anna Pinedo, who was also part of the team that left the former in February for Mayer Brown. Mayer Brown confirmed that Pinedo remains with the firm, where she currently serves as co-chair of its capital markets practice.

The American Lawyer reported in 2006 that Tanenbaum and his team were responsible for rapidly growing MoFo's New York office, although the group's desire to operate independently did not help it make friends among its new colleagues, some of who labelled the hires "The Royal Tanenbaums".