An asset has value, if it's value goes negative it's ceased to be an asset and become simply a liability. When I read the above, I imagined any number of my former professors, with raised eyebrows, saying "Mr. Rudeboy, that comment makes me want to check your status with the Registrar's Office."
How does an asset go negative? Even Enron stock could only go down to zero. I think x5452 should stop digging, he's plenty deep already.