a surplus or excess of money or merchandise that is actually on hand and that exceeds expectations
adj.
too old to be useful; "He left the house...for the support of twelve superannuated wool carders"- Anthony Trollope; overaged, superannuated, over-the-hill
Bloomberg Financial Glossary
Apples mainly to convertible securities. Difference between how much common stock one party must sell and the other wishes to buy for the same amount of convertible in a swap.