Embattled Swedish landlord SBB is facing an inflection point after one of its creditors demanded its money back, the first time such a written notice has been given.

Stockholm-based Samhallsbyggnadsbolaget i Norden AB — as the firm is officially known — has been at the center of Sweden’s property crisis as landlords scramble to find ways to refinance billions of dollars of bonds amassed in the cheap-money era. Now one of those bondholders has run out of patience, saying repayment is needed on the grounds SBB breached a key term in its debt.