Anatomy of a $576,000 mistake

The state Department of Assessments and Taxation has used worksheets to calculate property tax discounts under Baltimore’s historic credit program. The worksheet for The Atrium at Market Center apartments contains multiple, repeated errors starting in 2004. Over seven years the city underbilled the owner by $576,000.

The 10-year credit should be based only on a rehab's value, with large properties like the Atrium getting 80 percent of the break the first five years, followed by shrinking percentages. But the state didn't lock in the Atrium's $9.76 million post-rehab value, instead wrongly using each year's value during a rising real estate market.

Compounding the errors, the state used 80 percent in years when lower percentages were required by law. State officials confirmed The Sun's findings, attributing them to “clerical error.” Here is a breakdown of the four types of errors that resulted in the $576,000 underbilling: