Based on your second sentence, I don't think you mean the word 'mismanaged' here. That would imply those inside the company are intentionally trying to lower its value.

I think what you mean is, potential buyers are bad-mouthing the company, or deliberately talking down it's value in public to try to get a better deal.

Edit: It occurred to me, this could have been a substitution error of 'mismanaged,' for 'misrepresented.'