[rchaud]

Economic profit is still there, it's abnormal profits that would go to zero. With zero EP the opportunity cost of staying in business would be to high.

With 0 AP, the industry is in equilibrium, with no companies dropping out, and no companies entering the market.

[sclarisse]

The economic profit is literally defined as the accounting-type profits, minus the opportunity costs. When the opportunity cost is large like that you are describing negative economic profit.