Implementation of the Patient Protection and Affordable Care Act (Affordable Care Act, or ACA) is having a significan t impact on federal mandatory—also known as direct—spending. Most of the projected spending under the law is for expanding health insurance coverage. This includes premium tax credits and cost-sharing reduction payments for individuals and families who purchase private insurance coverage through the health insurance exchanges established under the ACA, as well as federal matching funds for states that choose to expand their Medicaid programs. The Internal Revenue Service (IRS) reports that spending on the premium tax credits and cost-sharing reductions totaled $79.2 billion for first three fiscal years (i.e., FY2014-FY2016) in which the ACA exchanges were operational. An analysis of preliminary data from the Medicaid Budget and Expenditure System (MBES) released by the Centers for Medicare and Medicaid Services (CMS) provides some insight into the initial impact of the Medicaid expansion on spending. For calendar year 2014, the 27 states that implemented the expansion reported spending a total of $36.7 billion on newly eligible adults, which under the ACA was paid for entirely with federal funds (i.e., 100% federal match). The same states spent an additional $10.5 billion on adults that were previously eligible at traditional federal match rates or subject to technical adjustments. Expenditures for these individuals were subject to a higher rate than the traditional match rate, but not 100%. In its March 2016 baseline budget projections, the Congressional Budget Office (CBO) estimates that gross spending on insurance coverage expansion under the ACA will total $1.938 trillion over the 10-year period FY2017 through FY2026. That total includes $866 billion on exchanges subsidies—premium tax credits and cost-sharing reductions—and related spending, and $1.063 trillion on Medicaid and the State Children's Health Insurance Program (CHIP). CBO projects that these costs will be offset by revenues from the ACA's taxes and fees, and by savings from the law's changes to the Medicare program that are designed to slow the rate of growth of Medicare payments to certain health care providers. The ACA also included numerous appropriations that are providing billions of dollars in mandatory funds to support new and existing grant programs and other activities. Several other provisions in the law require the Secretary of Health and Human Services (HHS) to transfer amounts from the Medicare Part A and Part B trust funds for specified purposes. This report summarizes all the mandatory appropriations and Medicare trust fund transfers in the ACA and provides details, where publicly available, on the status of obligation of these funds. The information is presented in two tables. The report also includes a brief discussion of the impact that sequestration is having on ACA mandatory spending. This report is periodically revised and updated to reflect important legislative and other developments. A companion CRS report discusses the ACA's impact on discretionary spending, which is controlled by the annual appropriations process. Discretionary spending under the ACA falls into two broad categories. First, there are the amounts provided in appropriations acts for specific grant and other programs pursuant to explicit authorizations of appropriations in the ACA. Second, there are the costs incurred by the federal agencies that are responsible for administering and enforcing the ACA's core provisions to expand insurance coverage. Table 2 summarizes all the ACA provisions that include an appropriation of funds or a transfer of amounts from the Medicare trust funds. The provisions are grouped under the following headings: (1) Private Health Insurance; (2) Medicaid and the State Children's Health Insurance Program (CHIP); (3) Medicare; (4) Fraud and Abuse; (5) Health Centers; (6) Health Workforce and the National Health Service Corps; (7) Community-Based Prevention and Wellness; (8) Maternal and Child Health; (9) Long-Term Care; (10) Comparative Effectiveness Research; (11) Biomedical Research; and (12) ACA Implementation: Administrative Expenses. Each table row provides information on a specific ACA provision, organized across four columns. The first column shows the ACA section or subsection number. The second column indicates whether the provision is freestanding (i.e., statutory authority that is not amending an existing statute) or amendatory (i.e., amends an existing statute, typically the Social Security Act). Amendatory provisions either add a new program to the statute or modify an existing one. The third column gives a brief description of the program or activity, including details of the appropriation or fund transfer. The entry also includes the name of the administering agency within HHS and, if applicable, the Catalog of Federal Domestic Assistance (CFDA) number for the grant program. The fourth column shows how much funding has been obligated to date. An agency incurs an obligation, for example, by placing an order, signing a contract, awarding a grant, purchasing a service, or taking other actions that require the government to make payments. The obligation amounts are based on information in the HHS Tracking Accountability in Government Grants System (TAGGS) unless specified otherwise. The TAGGS database is a central repository for grants awarded by all the HHS operating divisions (agencies) and several offices within the Office of the Secretary. It is updated daily with new data provided by these entities. In many instances the ACA provided annual appropriations of specified amounts for one or more fiscal years. Generally, these funds must be obligated during the fiscal year in which the funds become available for obligation. A few provisions are multiple-year appropriations , in which the amount appropriated is available for obligation for a period of time in excess of one fiscal year (e.g., for the period FY2011 through FY2014). Often the provision includes additional language stating that the funds are to remain available "until expended" or "without fiscal year limitation." Most ACA appropriations and fund transfers are temporary (i.e., time-limited). Often they end in FY2014 or FY2015, though in a handful of instances they extend until FY2019. The law included four provisions (i.e., Sections 3021(a), 3403, 10323(b), and 4002) that continue to provide annual or multiple-year appropriations in perpetuity. The ACA also included three indefinite appropriations that provide an unspecified amount of funding as indicated by the phrase "such sums as may be necessary," or SSAN. One such provision (i.e., Section 1311) appropriated SSAN and authorized the HHS Secretary to determine the specific amount necessary for the grant program. Table 3 provides additional details on each of the appropriations (and fund transfers) summarized in Table 2 . It shows the amount available for obligation in each fiscal year (or multi-year period) over the 10-year period FY2010 through FY2019. Note that the provisions are organized and grouped under the same headings used in Table 2 . The final column in Table 3 ("Total") shows for each provision the total amount of appropriations or fund transfers. Note that in several cases the total amount has yet to be determined (see table entries for Sections 1311, 3403, 6301(d) & (e), 9023(e), and 10323(a)). For three of the provisions that continue to provide funding beyond FY2019, the amount in the total column represents the cumulative amount appropriated through FY2019 (see table entries for Sections 3021(a), 4002, and 10323(b)). Unless otherwise stated, references to the Secretary in both tables refer to the HHS Secretary. A list of the federal laws, agencies, programs, and funds referred to in this report by their acronym is provided in Appendix A . As summarized in the tables, the ACA funded a broad range of new and existing programs. The law appropriated significant amounts to support the following short-term health care programs for targeted groups prior to the health insurance exchanges becoming operational in 2014: (1) $5 billion for the Pre-Existing Condition Insurance Plan (PCIP), a temporary insurance program that provided health insurance coverage for uninsured individuals with a pre-existing condition; (2) $5 billion for a temporary reinsurance program to reimburse employers for a portion of the costs of providing health benefits to early retirees aged 55-64; and (3) $6 billion for the Consumer Operated and Oriented Plan (CO-OP) program, to support temporary health insurance cooperatives. The ACA appropriated $2.4 billion for maternal and child health programs and provided an unspecified amount of funding for state grants to plan and establish health insurance exchanges. The law established the Center for Medicare and Medicaid Innovation (CMMI) within CMS and appropriated $10 billion for the FY2011-FY2019 period—and $10 billion for each subsequent 10-year period—for CMMI to test and implement innovative payment and service delivery models. It also established and funded an Independent Payment Advisory Board (IPAB) to make recommendations to Congress for achieving specific Medicare spending reductions if costs exceed a target growth rate. IPAB's recommendations are to take effect unless Congress overrides them, in which case Congress would be responsible for achieving the same level of savings. The ACA created four special funds and appropriated substantial amounts to each one: The Community Health Center Fund (CHCF) , to which the ACA appropriated a total of $11 billion in annual appropriations over the five-year period FY2011-FY2015, has helped support the federal health centers program and the National Health Service Corps (NHSC). (Note: A separate ACA appropriation provided $1.5 billion for health center construction and renovation.) Congress has since appropriated two additional years of funding for the CHCF (see below).