Jonathan Bush, a nephew of one president and cousin of another, stepped down as chief executive of Athenahealth under intensifying pressure from Elliott Management, which in May 2018 made a hostile takeover offer for the company. The $35 billion hedge fund is renowned for its use of sharp-elbowed tactics to accomplish its investing goals. Late in May, a 2005 court filing that accused Mr. Bush of hitting his ex-wife surfaced. A few days later, Bloomberg News reported on a 2007 complaint filed with Massachusetts regulators by a female employee who cited inappropriate conduct by Mr. Bush. Mr. Bush, 49, is a nephew of President George Bush and a cousin of President George W. Bush. Athenahealth, based in the Boston suburb Watertown, provides billing and other digital services for 114,000 medical providers and stores more than 110 million patient records. Mr. Bush, who worked as a New Orleans ambulance driver during college and afterward enlisted in the Army as a medic, founded the company that would become Athenahealth in 1997. It evolved into a technology firm that provided digital services to medical offices and digitally stored patient records. He worked as a management consultant with Booz Allen & Hamilton, a provider of management and technology consulting services to the United States government. Mr. Bush received his B.A. in the College of Social Studies from Wesleyan University and his M.B.A. from Harvard Business School.