Well if you consider that they have lumbered a huge amount of debt onto the company since then and that their position domestically and particularly in Europa has slipped it doesnt seem that odd for their value to have decreased. Anybody buying them now would be taking on debts which have a huge effect on their future profitability
I am not sure if they did, but there were speculations a while back that they were taking a huge obligations loan in the market, which would improve their cash flow, but at some stage they will have to cough up the 500 mill USD that they borrowed.