A number of tax provisions either expired in 2011 or are scheduled to expire at the end of 2012. These include the following: The Bush tax cuts, which reduced income taxes by reducing tax rates, reducing the marriage penalty, repealing limitations on personal exemptions and itemized deductions (PEP and Pease, respectively), expanding refundable credits, and modifying education tax incentives. The Bush tax cuts also reduced estate tax liabilities by increasing the amount of an estate exempt from taxation and by lowering the tax rate; The alternative minimum tax (AMT) patch, which, by increasing the amount of income that is exempt from the AMT and allowing certain personal credits against the AMT, prevents an estimated 26 million additional taxpayers from owing the AMT; The payroll tax cut, which reduced an employee's share of Social Security taxes by two percentage points; A variety of previously extended temporary tax provisions, commonly referred to as "tax extenders," which affect individuals, businesses, charitable giving, energy, community development, and disaster relief. As Congress decides whether to extend these provisions, it may consider the estimated revenue losses associated with their extension. The Congressional Budget Office (CBO) estimated that extending these provisions through 2022, except for the payroll tax cut, which CBO assumes expires as scheduled at the end of 2012, would reduce revenues by $5.4 trillion between 2013 and 2022. Specifically, over this 10-year budgetary window extending the Bush tax cuts and extending the AMT patch would reduce revenues by $4.6 trillion, while extending the tax extenders would reduce revenues by $839 billion. The cost of extending the payroll tax cut for one year (2012) was estimated to be $114 billion over the 2012-2022 budgetary window. In addition to budgetary cost, Congress may also consider other factors when evaluating tax policy. For example, when considering extending the Bush tax cuts, policy makers might consider that the majority of the benefits of this policy accrued to the top 20% of taxpayers. They might also evaluate the potential contractionary impact the expiration of these cuts in 2013 may have on the economy, especially since both the scheduled expiration of the payroll tax cut and the enactment of budget cuts as part of the Budget Control Act (P.L. 112-25) are scheduled to go into effect at the same time. Similarly, Congress may examine the cost effectiveness of the payroll tax cut. According to CBO, the short-term stimulus impact of the payroll tax cut is lower than increasing aid to the unemployed or providing additional refundable tax credits to low- and middle-income households, but more stimulative than extending the Bush tax cuts. Finally, Congress may weigh the lower budgetary costs of short-term extensions of tax extenders against the unpredictability for taxpayers that can arise from short-term extensions. In past years, Congress has extended expiring provisions en masse in one legislative vehicle. In the 112th Congress, Members have considered legislation to extend certain provisions, including S. 3412, S. 3413, and H.R. 8, which extend some or all of the Bush tax cuts and the AMT patch. In addition, the Senate may consider S. 3521, which extends certain temporary expiring provisions.