The U.S.-based company said Monday that financing is no longer available, and it continues to claim, as it has for months, that Apollo breached the terms of the agreement.
The boards of both companies and Cooper shareholders had approved the buyout, but negotiations with the union representing Cooper employees became a challenge.
Cooper took its claim to a Delaware court, but the court ruled last month that Apollo did not breach its obligation to quickly reach a pact with the United Steelworkers union.
Cooper did not further elaborate Monday on how it believes on how Apollo ignored terms of the deal and did not immediately respond to a request seeking comment.
The company did say that it's become clear that the deal signed in June will not close.
Shares of Cooper fell 6.6 percent, or $1.51, to $21.45 before markets opened.