NEW YORK (AP) — Valeant Pharmaceuticals is teaming up with activist investor Bill Ackman in a bid for Botox maker Allergan that could be worth about $40 billion.

Valeant said Monday that it intends to propose a merger with Allergan using a combination of Valeant stock and cash. The transaction size has not been disclosed, but Valeant expects the cash portion of the deal to be at least $15 billion.