Members of Congress are required to file personal financial disclosure reports every year, but keeping track of their personal finances is still a challenge. Lawmakers are required to file the disclosure reports by May 15, and they're made public in June of each year -- but only on paper.
The nonpartisan research group the Center for Responsive Politics picks up the thick reports, pours through the data, and makes it available online -- a process that typically takes more than four months.
Given that the data is only released just once a year and the Center has yet to compile 2010 data, the latest information available relies on 2009 data. The slides that follow are the 10 wealthiest senators, according to the 2009 reports.
Members of Congress are only required to report their wealth and liabilities in broad ranges, so the Center calculated each member's average estimated wealth by determining the minimum and maximum value of their assets. Additionally, federal financial disclosures don't require members of Congress to report certain assets such as personal residences.