“The proposal to change the measure of inflation used for federal programs to chained CPI, which rises more slowly than conventional inflation measures, is usually framed as a Social Security cut. And it is. The CBO estimates that it will save $133 billion in Social Security costs over 10 years. But it’s also a tax increase. Currently, the cutoffs for different tax brackets rise with CPI-U, a non-chained measure of inflation. Chained CPI would cause the cutoffs to rise more slowly, pushing more and more people into higher tax brackets. That raises $99 billion over 10 years. So about 43 percent of the deficit reduction from chained CPI comes from increased taxes.”
http://www.economicpolicyjournal.com/2013/05/the-truth-chained-cpi-is-worse-than-you.html