Combined Old-Age, Survivors, and Disability Insurance-Income Tax Reporting Amendments

Combined Old-Age, Survivors, and Disability Insurance - Income Tax Reporting Amendments - Directs the Secretary of the Treasury to make available specified tax returns to the Secretary of Health, Education, and Welfare.

Empowers the Secretary of HEW and the Secretary of the Treasury to enter into an agreement for the processing of information contained in such returns.

Requires the Secretary of the Treasury to provide to the Secretary of HEW any documents they agree are necessary for such processing.

Directs the Managing Trustee of the Trust Funds established pursuant to the Social Security Act, including the Federal Hospital Insurance Trust Fund and the Federal Supplementary Medical Insurance Trust Fund, to pay into the Treasury the amounts he and the Secretary of HEW estimate will be expended from the general fund of the Treasury by the Departments of HEW and Treasury for the administration of (1) titles II and XVIII of the Social Security Act, and (2) specified chapters and subchapters of the Internal Revenue Code.

Requires the Secretary of HEW to apportion (between each trust fund and the general fund in the Treasury) the costs of administrating titles II, XVI and XVIII of the Social Security Act and its costs in carrying out specified functions of this Act.

Revises the formula by which the adjustment to the contribution and benefit base is to be computed following an increase in social security benefits.