Here's Why Wall Street Doesn't Like The Return Of JCPenney's Old CEO

The news that Ron Johnson was out sent JC Penney's stock up nearly 11 percent. Then we found out that Mike Ullman would be his interim replacement hit, and the stock immediately plummeted.

There's a reason for that.

While Johnson erred on the side of changing too much too fast. Ullman is on the other, equally bad side of the spectrum. In his 6 years at JC Penney, he failed to make the changes the company desperately needed.

Hedge fund manager Bill Ackman explained his support for Johnson in a 2012 presentation. We've excerpted the parts that explain why Ullman failed.