A $5,200 unpaid water bill let two German real-estate investors lay claim for a brief moment to a cherished piece of Baltimore real estate: the Ravens football stadium.

The arrears landed M&T Bank Stadium in Baltimore’s annual tax sale, in which bidders vie to pay a property owner’s municipal debt, in return for the right to collect up to 18% interest, plus the principal from the owner. If the debt remains unpaid, the lien-holder can eventually foreclose on the property.

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