His technology would offer no perceived advantage in a sports-shoe sector that values performance first, and his expansion into clothes must worry investors.

The return on assets fell slightly, nothing that should worry investors.

That's the kind of short-termist tactic that should really worry investors.

Being targeted by one of the wiliest investors in the sector will worry investors, especially because shares in the companies have already dropped so much in value.

Yet there are three things that should worry investors.