2012 Tax Changes   * PAYROLL TAX CUT for employees extended through February 29, 2012. ( Social security tax rate on wages up to $ 110,100 will be 4.2 % rather than 6.2 %. ) * ADOPTION TAX CREDIT decreases to $ 12,650 for adoption of an eligible child. * SECTION 179 maximum deduction decreases to $ 139,000, with a phase-out threshold of $ 560,000. * STANDARD MILEAGE RATE for business driving remains at 55.5 ¢ a mile. Rate for medical and moving mileage decreases to 23 ¢ a mile. Rate for charitable driving remains at 14 ¢ a mile. * ESTATE TAX top rate remains at 35 %, and the exemption amount increases to $ 5,120,000. The ANNUAL GIFT TAX EXCLUSION remains at $ 13,000. * 401(k) maximum salary deferral increases to $ 17,000 ( $ 22,500 for 50 and older ). * SIMPLE maximum salary deferral remains at $ 11,500 ( $14,000 for 50 and older ). * IRA contribution limit remains at $ 5,000 ( $ 6,000 for 50 and older ). * KIDDIE TAX threshold remains at $ 1,900 and applies up to age 19 ( up to age 24 for full-time students ). * NANNY TAX threshold increases to $ 1,800. * TRANSPORTATION FRINGE BENEFIT limit decreases to $ 125 for vehicle/transit passes and increases to $ 240 for qualified parking. * SOCIAL SECURITY taxable wage limit increases to $ 110,100. Retirees under full retirement age can earn up to $ 14,640 without losing benefits. * HSA CONTRIBUTION limit increases to $ 3,100 for individuals and to $ 6,250 for families. An additional $ 1,000 may be contributed by those 55 or older.