A new experimental package, Finance-Treasury, has been uploaded to hackage. It automates the fetching of Treasury's daily yield curve data (XML) and translates the data into Data.Map representation. The collection of historical data can go back to 1992. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Finance-Treasury The APIs are largely working. But the internal code still needs improvement. Welcome suggestions and fixes. Recommendation on proper error handling design will be particularly appreciated. steve