Lease capitalisation removed the largest historical example, but plenty remain: supply chain finance, receivables factoring, unconsolidated joint ventures, purchase commitments and guarantees given to affiliates. Each moves an obligation somewhere less visible.
The discipline is to read the commitments and contingencies note in the form-10-k and add anything that behaves like debt to total-debt before computing leverage.
Example: Northwind Tools discloses $85M of non-cancellable purchase commitments for battery cells and a $40M guarantee on a joint venture's loan. Neither appears on the balance sheet; both are real.
Related: contingent-liability, total-debt, footnotes, related-party-transaction, form-10-k