Guarantees are essential features of commercial financing transactions. But the nature of the guarantor’s liability may vary significantly. Is the guarantor liable only when the underlying obligor has defaulted on its obligations (a “see to it” guarantee) – or as soon as the guarantee’s beneficiary makes a good faith demand (an “on demand” guarantee)? Shanghai v Reignwood [2021] EWCA 1147 (Court of Appeal) illustrates the importance of the distinction, and how it can turn on fine points of construction.