RE:Existing Shareholder EquityI interpret it this way:
Impairment is when the market/fair value of the asset is less than the carrying/book value. When this occurs, the asset is deemed to be impaired and the company must reduce the book value to match the current fair value .
Example: Your bought a car, and the current loan outstanding (book value) is $20K. You can only sell (fair value) it for $15K. Your asset to be imparied by $5K.
In the accounting world, you would immediately reduce the book value of your asset by $5K (the impaired value) - or pay down your loan to match the value.
Assets = Liability + Owner's Equity
If Assets are going down (impaired) and you still owe money to creditors, then the only way to balance the equation is to reduce owners equity (shareholder value).
TID example
Assets: 500 = Liabilities:300 + Equity: 200
If TID now says that your assets are actually on worth 300, then you have to reduce the equation to balance
Updated Asset Value: 300 (500 - 200) = Liabilities 300 + Equity 200 - Impairment Charge 200
300 = 300 + 200 - 200
Assets: 300 = Liabilities: 300 + Equity:0
You have effectively reduced owners equity (share value) to zero by recording an impariment charge against your assets.
I believe they now state "Impaired - deemed to reject' Otherwise known as - if I sell the assets, I can pay my loan and there is nothing left over for owners.