The billionaire supermarket magnate Ron Burkle's increasingly acrimonious battle against the Riggio family which controls Barnes & Noble, the No 1 bookseller in the US, is headed for the courts.
Mr Burkle has filed a lawsuit challenging the poison pill provision introduced by the company last November after he began accumulating a stake and agitating for management changes.
Leonard Riggio, the chairman, began the company in 1965 with a single store. The Riggio family and other insiders own 31 per cent of the company, and are allowed to issue shares to dilute the holding of other investors in order to thwart a takeover. Mr Burkle has just under 20 per cent.
The lawsuit charges the board with breaching its fiduciary duty by "adopting and maintaining a discriminatory poison pill without any legitimate corporate purpose," according to the filing.
Barnes & Noble said it would fight the suit. "Mr Burkle has filed this meritless lawsuit to advance his own self-serving agenda," its board said in a statement.
Mr Burkle targeted Barnes & Noble last year after becoming angry that in an era when book sales were increasingly moving online, the company had agreed to acquire a chain of college bookstores – from Mr Riggio.