Proposed Provision: H5. Beginning in 2029, for single/head-of-household/married-filing-separate taxpayers with MAGI of $250,000 or more and joint filers with MAGI of $500,000 or more, include up to the remaining 15 percent of Social Security benefits in taxable income (increased from up to 85 percent of benefits taxable under current law). In subsequent years, update these thresholds for growth in wages (AWI). Revenue from this provision would be credited to the Social Security trust funds. Current law taxation of up to 85 percent of Social Security benefits would remain unchanged.