EBITDA

earnings before interest, taxes, depreciation (Abschreibungen - auf Sachanlagen) and amortization
(auf immaterielle Vermögensgegenstände inkl. Firmenwert. The inclusion of depreciation creates a lot of discussion since it is often a very good approximation of the capital expenditures required to maintain the asset base.

Leverage: Debt/EBITDA >3 is unhealthy

Interest Cover: (EBITDA/Interest Expense)<1 is not sustainable