Think about it - A company is required to give me $1000 in 5 years. That is a liability. One year passes. Would you say the liability is now $800 through amortization (or some other amortized number)? You still owe me $1000. If you want to amortize the liability you would need to redeem shares through a sinking fund or similar.

The liability itself? No, of course not.

According to GAAP, mandatorily redeemable preferred stock sold on SEC must be accounted for as a liability rather than equity. Do we amortize the liability over the life of the preferred shares?