After the Arizona Daily Star learned banks bailed out by taxpayers had become the main players in the purchase of tax liens, the newspaper set out to determine what banks were buying tax liens and how much they were buying.

To find the banks, the Star interviewed sources, searched corporation records across the country, researched Securities and Exchange Commission filings and searched corporate records in Delaware, where many LLCs and trusts are located. The Star found five banks that either bought liens directly in Pima County or set up trusts for institutional investors to buy them.

To determine how much they bought, the Star obtained and analyzed five years' worth of tax-lien sales. from the Pima County Treasurer's Office. The newspaper also analyzed five years of Maricopa County tax-lien data.

The Star also analyzed a list of all foreclosures in Pima County since August 2009, obtained from, to identify the more than 3,050 foreclosures by those banks that have been buying up tax liens.

Finally, the Star mapped the 5,850 tax liens bought by the five banks in the past three years, and the more than 3,050 foreclosures in the past nearly two years.