NEW YORK - Aimia Inc.'s (AIM:CT) largest investor has filed a counterclaim against the loyalty company and six current and former members of the board.

Mittleman Brothers also filed a statement of defence in the Ontario Superior Court of Justice that rebuts Aimia's July lawsuit accusing the dissident investor of violating a contracted truce.

The litigious showdown is the latest development in a drawn-out battle over control of the board of directors.

In a statement, Chris Mittleman called it “extremely disappointing” that the Aimia board opted to take matters to the courts, saying shareholders “deserve nothing less” than seasoned business professionals.

Mittleman's counterclaim names Aimia chairman Bill McEwan, chief executive Jeremy Rabe, former chairman Robert Brown, board members Thomas Gardner and Robert Kriedler and former board member Emma Griffin.

Aimia's lawsuit accuses Mittleman, which owns 23.2 per cent of the company, of continuing to advocate for radical change during a “standstill agreement” and attempting to orchestrate a covert campaign to encourage other shareholders to withhold their support for Aimia's nominees at the 2019 annual meeting.