The District of Columbia struck an unprecedented number of deals behind closed doors this year with prominent commercial property owners who had appealed their tax assessments, reducing the city's tax base by $2.6 billion. The settlements were kept from the public for months until The Washington Post started mining public records and filing FOIAs, which the city routinely denied until the newspaper's lawyers got involved. The Post also learned that city leaders had kept critical internal audits about the tax office in "draft" format to prevent their release under FOIA. Through sources, The Post obtained the undisclosed reports -- along with a dozen other audits that had been kept from public view -- and published the findings for the first time. The series prompted the City Council to change the law to require the tax office to immediately make public all of its reports -- bringing a new level of transparency to a once secretive agency. The Securities and Exchange Commission also launched a probe to see if the city had kept critical findings from audits used to determine bond ratings. The inquiry is ongoing.