Status of the 

Social Security 

and Medicare 

Programs

A SUMMARY OF THE

2017 ANNUAL REPORTS

Social Security and Medicare

Boards of Trustees

2017
The Social Security and Medicare Trustees Reports, as well as

this document, are available at the following addresses:

Social Security (OASDI): www.ssa.gov/OACT/TR/2017/

Medicare (HI and SMI): www.cms.gov/Research-Statistics-Data-and-Systems/Statistics-Trends-and-Reports/ReportsTrustFunds/

Summary: www.ssa.gov/OACT/TRSUM/

Other information about Social Security benefits and services is available at

www.ssa.gov or by calling toll-free 1-800-772-1213.

Other information about Medicare benefits and services is available at

www.cms.gov or by calling toll-free 1-800-633-4227.
A MESSAGE TO THE PUBLIC:

Each year the Trustees of the Social Security and Medicare trust funds 

report on the current and projected financial status of the two programs. 

This message summarizes the 2017 Annual Reports. 

Both Social Security and Medicare face long-term financing shortfalls 

under currently scheduled benefits and financing. Lawmakers have a 

broad continuum of policy options that would close or reduce the longterm financing shortfall of both programs. The Trustees recommend that 

lawmakers take action sooner rather than later to address these shortfalls, so that a broader range of solutions can be considered and more 

time will be available to phase in changes while giving the public adequate time to prepare. Earlier action will also help elected officials minimize adverse impacts on vulnerable populations, including lower-income 

workers and people already dependent on program benefits. 

Social Security and Medicare together accounted for 42 percent of Federal program expenditures in fiscal year 2016. The unified budget reflects 

current trust fund operations. Consequently, even when there are positive 

trust fund balances, any drawdown of those balances, as well as general 

fund transfers into Medicare’s Supplementary Medical Insurance (SMI) 

fund and interest payments to the trust funds that are used to pay benefits, 

increase pressure on the unified budget. Both Social Security and Medicare will experience cost growth substantially in excess of GDP growth 

through the mid-2030s due to rapid population aging caused by the large 

baby-boom generation entering retirement and lower-birth-rate generations entering employment. For Medicare, it is also the case that growth 

in expenditures per beneficiary exceeds growth in per capita GDP over 

this time period. In later years, projected costs expressed as a share of 

GDP rise slowly for Medicare and are relatively flat for Social Security, 

reflecting very gradual population aging caused by increasing longevity 

and slower growth in per-beneficiary health care costs. 

Social Security

The Social Security program provides workers and their families with 

retirement, disability, and survivors insurance benefits. Workers earn 

these benefits by paying into the system during their working years. Over 

the program’s 82-year history, it has collected roughly $19.9 trillion and 
paid out $17.1 trillion, leaving asset reserves of more than $2.8 trillion at 

the end of 2016 in its two trust funds. 

The Old-Age and Survivors Insurance (OASI) Trust Fund, which pays 

retirement and survivors benefits, and the Disability Insurance (DI) Trust 

Fund, which pays disability benefits, are by law separate entities. However, to summarize overall Social Security finances, the Trustees have traditionally emphasized the financial status of the hypothetical combined 

trust funds for OASI and DI. The combined funds—designated OASDI— 

satisfy the Trustees’ test of short-range (ten-year) financial adequacy. The 

Trustees project that the combined fund asset reserves at the beginning of 

each year will exceed that year’s projected cost through 2029. However, 

the funds fail the test of long-range close actuarial balance.

The Trustees project that the combined trust funds will be depleted in 

2034, the same year projected in last year’s report. The projected 75-year 

actuarial deficit for the OASDI Trust Funds is 2.83 percent of taxable 

payroll, up from 2.66 percent projected in last year’s report. This deficit 

amounts to 1 percent of GDP over the 75-year time period, or 21 percent 

of program non-interest income, or 17 percent of program cost. A 0.05 

percentage point increase in the OASDI actuarial deficit would have been 

expected if nothing had changed other than the one-year shift in the valuation period from 2016 through 2090 to 2017 through 2091. The effects of 

recently enacted legislation, updated demographic and economic data, 

and improved methodologies further increased the actuarial deficit by 

0.12 percent of taxable payroll.

Social Security’s total income is projected to exceed its total cost through 

2021, as it has since 1982. The 2016 surplus of total income relative to 

cost was $35 billion. However, when interest income is excluded, Social 

Security’s cost is projected to exceed its non-interest income throughout 

the projection period, as it has since 2010. The Trustees project that this 

annual non-interest deficit will average about $51 billion between 2017 

and 2020. It will then rise steeply as income growth slows to its sustainable trend rate as the economic recovery is complete while the number of 

beneficiaries continues to grow at a substantially faster rate than the 

number of covered workers. 

After 2021, interest income and redemption of trust fund asset reserves 

from the General Fund of the Treasury will provide the resources needed 
to offset Social Security’s annual deficits until 2034, when the OASDI 

reserves will be depleted. Thereafter, scheduled tax income is projected to 

be sufficient to pay about three-quarters of scheduled benefits through the 

end of the projection period in 2091. The ratio of reserves to one year’s 

projected cost (the combined trust fund ratio) peaked in 2008, declined 

through 2016, and is expected to decline steadily until the trust funds are 

depleted in 2034. 

Under current projections, the annual cost of Social Security benefits 

expressed as a share of workers’ taxable earnings will grow from 

13.7 percent in 2016 to roughly 17.0 percent in 2038, and will then 

decline slightly before slowly increasing after 2051. Costs display a 

slightly different pattern when expressed as a share of GDP. Program 

costs equaled 5.0 percent of GDP in 2016, and the Trustees project these 

costs will increase to 6.1 percent of GDP by 2037, decline to 5.9 percent 

of GDP by 2050, and thereafter rise slowly reaching 6.1 percent by 2091. 

While the projections for the combined trust funds are somewhat less 

favorable than last year, the projections for the DI Trust Fund are more 

favorable. Provisions in the Bipartisan Budget Act of 2015 that became 

law in November 2015 were projected to postpone depletion of the DI 

Trust Fund by six years to 2022 from 2016 under the assumptions of the 

2015 Trustees Report, largely by temporarily reallocating a portion of the 

payroll tax rate from the OASI Trust Fund to the DI Trust Fund. In last 

year’s report, the DI Trust Fund depletion date projection was extended 

one year to 2023. In this year’s report, the depletion date projection is 

being extended five additional years, to 2028, due to lower-than-expected 

recent applications for and awards of DI benefits. Nonetheless, this year’s 

projections for the OASI and OASDI Trust Fund depletion dates are 

unchanged, and the estimated magnitude of long-term financial imbalances is little changed for DI and is larger for OASDI. 

Medicare 

The Medicare program has two separate trust funds, the Hospital Insurance (HI) Trust Fund and the Supplementary Medical Insurance (SMI) 

Trust Fund. HI, otherwise known as Medicare Part A, helps pay for hospital, home health services following hospital stays, skilled nursing facility, 

and hospice care for the aged and disabled. SMI consists of Medicare 

Part B and Part D. Part B helps pay for physician, outpatient hospital, 
home health, and other services for the aged and disabled who have voluntarily enrolled. Part D provides subsidized access to drug insurance 

coverage on a voluntary basis for all beneficiaries, as well as premium 

and cost-sharing subsidies for low-income enrollees.

The Trustees project that the HI Trust Fund will be depleted in 2029, one 

year later than projected in last year’s report. At that time dedicated revenues will be sufficient to pay 88 percent of HI costs. The Trustees project 

that the share of HI cost that can be financed with HI dedicated revenues 

will decline slowly to 81 percent in 2041, and will then rise gradually to 

88 percent in 2091. The HI fund again fails the test of short-range financial adequacy, as its trust fund ratio is already below 100 percent of 

annual costs, and is expected to stay about unchanged to 2021 before 

declining in a continuous fashion until reserve depletion in 2029. 

The HI Trust Fund’s projected 75-year actuarial deficit is 0.64 percent of 

taxable payroll, which represents 0.3 percent of GDP through 2091, or 16 

percent of non-interest income, or 14 percent of program cost. This estimate is down from 0.73 percent of taxable payroll projected in last year’s 

report. This improvement reflects a 0.01 percentage point increase in the 

HI actuarial deficit that would have been expected if nothing had changed 

other than shifting the valuation period forward one year to 2017 through 

2091, and a 0.10 percentage point decrease due to new data and changed 

assumptions.

For SMI, the Trustees project that both Part B and Part D will remain 

adequately financed into the indefinite future because current law provides financing from general revenues and beneficiary premiums each 

year to meet the next year’s expected costs. However, the aging population and rising health care costs cause SMI projected costs to grow 

steadily from 2.1 percent of GDP in 2016 to approximately 3.4 percent of 

GDP in 2037, and to then increase more slowly to 3.7 percent of GDP by 

2091. General revenues will finance roughly three-quarters of SMI costs, 

and premiums paid by beneficiaries almost all of the remaining quarter. 

SMI also receives a small amount of financing from special payments by 

States, and from fees on manufacturers and importers of brand-name prescription drugs. 

The Trustees project that total Medicare costs (including both HI and SMI 

expenditures) will grow from approximately 3.6 percent of GDP in 2016 
to 5.6 percent of GDP by 2041, and will increase gradually thereafter to 

about 5.9 percent of GDP by 2091. 

In recent years U.S. national health expenditure (NHE) growth has 

slowed considerably. There is uncertainty regarding the degree to which 

this slowdown reflects the impacts of the recent economic downturn and 

other non-persistent factors, as opposed to structural changes in the 

health care sector that may continue to produce cost savings in the years 

ahead. It is possible that U.S. health care practices are becoming more 

efficient as new payment models develop and providers anticipate less 

rapid growth of reimbursement rates in both the public and private sectors than has occurred during the past several decades.

For a number of years, the methodology the Trustees have employed for 

projecting Medicare finances over the long term has assumed a substantial reduction in per capita health expenditure growth rates relative to 

historical experience. In addition, the Trustees have been revising down 

their projections for near-term Medicare expenditure growth in light of 

the recent favorable experience, in part due to effects of payment changes 

and delivery system reform that are changing health care practices. However, the Trustees have not assumed additional, specific cost saving arising from structural changes in the delivery system that may result from 

new payment mechanisms in the Medicare Access and CHIP Reauthorization Act of 2015 and the cost-reduction incentives in the Affordable Care 

Act, or from payment reforms initiated by the private sector. 

Notwithstanding the assumption of a substantial slowdown of per capita 

health expenditure growth, the projections indicate that Medicare still 

faces a substantial financial shortfall that will need to be addressed with 

further legislation. Such legislation should be enacted sooner rather than 

later to minimize the impact on beneficiaries, providers, and taxpayers.

Conclusion 

Lawmakers have many policy options that would reduce or eliminate the 

long-term financing shortfalls in Social Security and Medicare. Lawmakers should address these financial challenges as soon as possible. Taking 

action sooner rather than later will permit consideration of a broader 

range of solutions and provide more time to phase in changes so that the 

public has adequate time to prepare.
By the Trustees:

STEVEN T. MNUCHIN, Secretary of the Treasury,

and Managing Trustee 

of the Trust Funds.

R. ALEXANDER ACOSTA, Secretary of Labor,

and Trustee.

THOMAS E. PRICE, M.D.

Secretary of Health 

and Human Services,

and Trustee.

NANCY A. BERRYHILL, Acting Commissioner 

of Social Security,

and Trustee.
1

A SUMMARY OF THE 2017 ANNUAL SOCIAL SECURITY

AND MEDICARE TRUST FUND REPORTS

In 2016, Social Security’s reserves increased by $35 billion to reach 

$2.8 trillion by the end of the year. Under the intermediate assumptions, 

the Disability Insurance (DI) Trust Fund will be able to pay full benefits 

until 2028, five years later than projected in last year’s Social Security 

report. The improved outlook is due to recent declines in disability applications and lower projected disability incidence rates during the shortrange period. The Old-Age and Survivors Insurance (OASI) Trust Fund is 

able to pay full benefits until 2035, and the combined OASDI funds1 until 

2034, both unchanged from last year. Over the 75-year projection period, 

Social Security faces an actuarial deficit of 2.83 percent of taxable payroll, up from the 2.66 percent projected last year. The actuarial deficit 

equals 1.0 percent of GDP through 2091.

Reserves in Medicare’s two trust funds increased by $31 billion to a total 

of $295 billion at the end of 2016. The Hospital Insurance (HI) Trust 

Fund is projected to be able to pay full benefits until 2029, one year later 

than indicated in last year’s Medicare report. The HI actuarial deficit is 

0.64 percent of taxable payroll over the 75-year projection period, somewhat smaller than the 0.73 percent projected in last year’s report, and 

equivalent to 0.3 percent of GDP through 2091.

What Are the Trust Funds? Congress established trust funds managed 

by the Secretary of the Treasury to account for Social Security and Medicare income and disbursements. The Treasury credits Social Security and 

Medicare taxes, premiums, and other income to the funds. There are four 

separate trust funds. For Social Security, the OASI Trust Fund pays retirement and survivors benefits and the DI Trust Fund pays disability benefits. For Medicare, the HI Trust Fund pays for inpatient hospital and 

related care. The Supplementary Medical Insurance (SMI) Trust Fund 

comprises two separate accounts: Part B, which pays for physician and 

outpatient services, and Part D, which covers prescription drug benefits.

The only disbursements permitted from the funds are benefit payments 

and administrative costs. Federal law requires that all excess funds be 

invested in interest-bearing securities backed by the full faith and credit of 

the United States. The Department of the Treasury currently invests all 

program revenues in special non-marketable securities of the U.S. Government which earn interest equal to rates on marketable securities with 

durations defined in law. The balances in the trust funds, which represent 

the accumulated value, including interest, of all prior program annual surpluses and deficits, provide automatic authority to pay benefits.

1 OASDI is the designation for the two trust funds when they are considered on a hypothetical combined basis to illustrate the actuarial status of the program as whole. The OASI and DI Trust Funds 

are distinct legal entities which operate independently.
2

What Were the Trust Fund Operations in 2016? In 2016, 50.3 million 

people received OASI benefits, 10.6 million received DI benefits, and 

56.8 million were covered under Medicare. A summary of Social Security 

and Medicare trust fund operations is shown below (Table 1). All four 

trust funds increased asset reserves in 2016.

Table 2 shows payments, by category, from each trust fund in 2016.

Trust fund income, by source, in 2016 is shown in Table 3.

Table 1: TRUST FUND OPERATIONS, 2016

[In billions]

OASI DI HI SMI

Reserves (end of 2015) . . . . . . . . $2,780.3 $32.3 $193.8 $69.5

Income during 2016 . . . . . . . . . . 797.5 160.0 290.8 419.4

Cost during 2016. . . . . . . . . . . . . 776.4 145.9 285.4 393.3

Net change in reserves . . . . . . 21.1 14.1 5.4 26.1

Reserves (end of 2016) . . . . . . . . 2,801.3 46.3 199.1 95.6

Notes: Totals do not necessarily equal the sum of rounded components.

OASI and DI reserve figures for 2015 do not reflect benefit payments regularly scheduled for 

January 3, 2016, which were actually paid on December 31, 2015. These accelerated payments 

are allocated to 2016 costs. SMI reserves for 2015 do reflect premium payments and general 

revenue matching for SMI (Part B) regularly scheduled for January 3, 2016, which were 

received in 2015. Because January 3, 2016 was a Sunday, these income items moved to the next 

earliest date that was not a weekend or holiday.

Table 2: PROGRAM COST, 2016

[In billions]

Category OASI DI HI SMI

Benefit payments . . . . . . . . . . . . $768.6 $142.8 $280.5 $389.0

Railroad Retirement financial 

interchange . . . . . . . . . . . . . . . 4.3 0.4 — —

Administrative expenses . . . . . . 3.5 2.8 4.9 4.4

Total . . . . . . . . . . . . . . . . . . . . . . 776.4 145.9 285.4 393.3

Notes: Totals do not necessarily equal the sum of rounded components.

OASI and DI cost figures for 2016 include benefit payments regularly scheduled for January 

3, 2016, which were actually paid on December 31, 2015. 

Table 3: PROGRAM INCOME, 2016

[In billions]

Source OASI DI HI SMI

Payroll taxes . . . . . . . . . . . . . . . $678.8 $157.4 $253.5 —

Taxes on OASDI benefits . . . . . 31.6 1.2 23.0 —

Interest earnings . . . . . . . . . . . . 87.0 1.4 7.7 $2.1

General Fund reimbursements . 0.1 a 1.2 29.9

General revenues. . . . . . . . . . . . — — — 288.1

Beneficiary premiums . . . . . . . . — — 3.3 85.9

Transfers from States. . . . . . . . . — — — 10.0

Other . . . . . . . . . . . . . . . . . . . . . a a 2.1 3.4

Total. . . . . . . . . . . . . . . . . . . . . . 797.5 160.0 290.8 419.4

Notes: Totals do not necessarily equal the sum of rounded components. 

a Less than $50 million.
3

In 2016, Social Security’s total income exceeded total cost by $35 billion. 

When interest received on trust fund assets is excluded from program 

income, there was a deficit of non-interest income relative to cost equal to 

$53 billion. The Trustees project that annual non-interest-income deficits 

will persist throughout the long-range period (2017-91).

In 2016, the HI Trust Fund’s total income, consisting of $283 billion in 

non-interest income and $8 billion in interest income (Table 3), exceeded 

program expenditures ($285 billion). For SMI, general revenues, which 

are set prospectively based on projected costs, represent the largest source 

of income.

What Is the Outlook for Future Social Security and Medicare Costs 

in Relation to GDP? One instructive way to view the projected costs of 

Social Security and Medicare is to compare the costs of scheduled benefits and administrative costs for the programs with the gross domestic 

product (GDP), the most frequently used measure of the total output of 

the U.S. economy (Chart A).

Under the intermediate assumptions employed in the reports, the costs of 

these programs as a percentage of GDP increase substantially through 

2035 because: (1) the number of beneficiaries rises rapidly as the babyboom generation retires; and (2) the lower birth rates that have persisted 

since the baby boom cause slower growth of the labor force and GDP.

 Chart A–Social Security and Medicare Cost as a Percentage of GDP

0%

2%

4%

6%

8%

10%

1970 1980 1990 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090

Calendar year

OASI + DI

HI + SMI (including Part D)

Historical Estimated
4

Social Security’s annual cost as a percentage of GDP is projected to 

increase from 4.9 percent in 2017 to about 6.1 percent by 2037, then 

decline to 5.9 percent by 2050 before generally rising to 6.1 percent of 

GDP by 2091. Under the intermediate assumptions, Medicare cost rises 

from 3.6 percent of GDP in 2017 to 5.4 percent of GDP by 2035 due 

mainly to the growth in the number of beneficiaries, and then increases 

further to 5.9 percent by 2091. The growth in health care cost per beneficiary becomes the larger factor later in the valuation period, particularly 

in Part D.

In 2017, the combined cost of the Social Security and Medicare programs 

is estimated to equal 8.5 percent of GDP. The Trustees project an increase 

to 11.5 percent of GDP by 2035 and to 12.0 percent by 2091, with most of 

these increases attributable to Medicare. Medicare’s relative cost is 

expected to rise gradually from 74 percent of the cost of Social Security 

in 2017 to 96 percent by 2091. 

The projected costs for OASDI and HI depicted in Chart A and elsewhere 

in this document reflect the full cost of scheduled current-law benefits 

without regard to whether the trust funds will have sufficient resources to 

meet these obligations. Current law precludes payment of any benefits 

beyond the amount that can be financed by the trust funds, that is, from 

annual income and trust fund reserves. In years after trust fund depletion, 

the amount of benefits that would be payable is lower than shown because 

OASDI and HI, by law, cannot borrow money or pay benefits that exceed 

the asset reserves in their trust funds. The projected costs assume realization of the full estimated savings of the Affordable Care Act and the physician payment rate updates specified in the Medicare Access and CHIP 

Reauthorization Act (MACRA) of 2015. As described in the Medicare 

Trustees Report, the projections for HI and SMI Part B depend significantly on the sustained effectiveness of various current-law cost-saving 

measures, in particular, the lower increases in Medicare payment rates to 

most categories of health care providers.

What Is the Outlook for Future Social Security and Medicare HI 

Costs and Income in Relation to Taxable Earnings? Because the primary source of income for OASDI and HI is the payroll tax, it is informative to express the programs’ incomes and costs as percentages of taxable 

payroll—that is, of the base of worker earnings taxed to support each program (Chart B).

It is important to understand that the two programs have different taxable 

payrolls. HI taxable payroll is about 25 percent larger than that of OASDI 

because the HI payroll tax is imposed on all earnings while OASDI taxes 

apply only to earnings up to a maximum ($127,200 in 2017), which ordinarily is adjusted each year. Thus, the percentages in Chart B are comparable within each program, but not across programs.
5

Both the OASDI and HI annual cost rates rise over the long run from their 

2016 levels (13.70 and 3.38 percent). Projected Social Security cost 

grows to 17.02 percent of taxable payroll in 2038 and to 17.80 percent of 

taxable payroll in 2091. The projected Medicare HI cost rate rises to 

4.79 percent of taxable payroll in 2050, and thereafter increases to 

4.96 percent in 2091.

The OASDI and HI income rates in Chart B include payroll taxes and 

taxes on OASDI benefits, but not interest payments. The projected 

OASDI income rate is stable at about 13 percent throughout the longrange period. The HI income rate rises gradually from 3.35 percent in 

2016 to 4.36 percent in 2091 due to the Affordable Care Act’s increase in 

payroll tax rates for high earners that began in 2013. Individual tax return 

filers with earnings above $200,000, and joint return filers with earnings 

above $250,000, pay an additional 0.9 percent tax on earnings above 

these earnings thresholds. An increasing fraction of all earnings will be 

subject to the higher tax rate over time because the thresholds are not 

indexed. By 2091, an estimated 79 percent of workers would pay the 

higher rate.

How Will Cost Growth in the Different Parts of Medicare Change the 

Sources of Program Financing? As Medicare cost grows over time, 

general revenues and beneficiary premiums will play an increasing role in 

financing the program. Chart C shows scheduled cost and non-interest 

revenue sources under current law for HI and SMI combined as a percent-

 Chart B–OASDI and HI Income and Cost as Percentages 

of Their Respective Taxable Payrolls

0%

5%

10%

15%

20%

1970 1980 1990 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090

Calendar year

Income rates

Cost rates

Historical Estimated

OASDI

HI
6

age of GDP. The total cost line is the same as displayed in Chart A and 

shows Medicare cost rising to 5.9 percent of GDP by 2091.

Projected revenue from payroll taxes and taxes on OASDI benefits credited to the HI Trust Fund increases from 1.5 percent of GDP in 2017 to 

1.8 percent in 2091 under current law, while projected general revenue 

transfers to the SMI Trust Fund increase from 1.5 percent of GDP in 2017 

to 2.7 percent in 2091, and beneficiary premiums increase from 0.5 to 

0.9 percent of GDP during the same period. Thus, the share of total noninterest Medicare income from taxes declines (from 42 percent to 

33 percent) while the general revenue share rises (from 42 percent to 

48 percent), as does the share of premiums (from 14 percent to 

17 percent). The distribution of financing changes in large part because 

costs for Part B and especially Part D—the Medicare components that are 

financed mainly from general revenues—increase at a faster rate than Part 

A cost under the Trustees’ projections. The projected annual HI financial 

deficit beyond 2035 through 2091 averages about 0.3 percent of GDP and 

there is no provision under current law to finance that shortfall through 

general revenue transfers or any other revenue source.

The Medicare Modernization Act (2003) requires that the Board of Trustees determine each year whether the annual difference between program 

cost and dedicated revenues (the bottom four layers of Chart C) under 

current law exceeds 45 percent of total Medicare cost in any of the first 

 Chart C–Medicare Cost and Non-Interest Income by Source

as a Percentage of GDP

0%

1%

2%

3%

4%

5%

6%

7%

1970 1980 1990 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090

Calendar year

Historical Estimated

Payroll Taxes

Premiums

General Revenue

Transfers

Tax on OASDI Benefits

Total Non-Interest Income

Total Cost

State Transfers & Drug Fees

Deficit
7

seven fiscal years of the 75-year projection period, in which case the 

annual Trustees Report must include, as it did from 2006 through 2013, a 

determination of “excess general revenue Medicare funding.” Because 

that difference is expected to exceed the 45 percent threshold in fiscal 

year 2023, the Trustees are issuing a determination of projected excess 

general revenue Medicare funding in this year’s report.

What Are the Budgetary Implications of Rising Social Security and 

Medicare Costs? Discussion of the long-range financial outlook for 

Medicare and Social Security often focuses on the depletion dates for the 

HI and OASDI trust funds—the times when the projected trust fund balances under current law will be insufficient to pay the full amounts of 

scheduled benefits. Normal operations of the trust fund also have an 

impact on the unified Federal budget.

Under the OASDI and HI programs, when taxes and other sources of revenue are collected in excess of immediate program costs, funds are converted to Treasury bonds and held in reserve for future periods. 

Accumulation of assets in the trust fund improves the unified Federal 

budget position. When trust fund assets are drawn down to pay scheduled 

benefits, bonds are redeemed and interest payments are made, creating a 

current-year cost to the unified Federal budget.

Unlike HI and OASDI, SMI does not have a trust fund structure with surpluses accumulated from prior years. General revenues pay for roughly 

75 percent of all SMI costs and pose an immediate cost for the unified 

Federal budget.

Chart D shows the required SMI general revenue funding, plus the excess 

of scheduled costs over dedicated tax and premium income for the 

OASDI and HI trust funds expressed as percentages of GDP through 

2040. For OASDI and HI, the difference between scheduled cost and dedicated revenues is equal to interest earnings and asset redemptions prior to 

trust fund depletion, and unfunded obligations after depletion. The chart 

assumes full benefits will be paid after trust fund depletion, even though 

under current law expenditures can only be made to the extent covered by 

current income. Such budgetary assumptions are typical of unified budget 

baselines, but do not reflect current law in the Social Security Act, nor do 

they reflect policy approaches that Congress has used in the past.

In 2017, the projected difference between Social Security’s expenditures 

and dedicated tax income is $27 billion. The Trustees anticipate a small 

surplus of $3 billion in non-interest income for the HI program.1 The projected general revenue demands of SMI are $287 billion. Thus, the total 

general revenue requirements for Social Security and Medicare in 2017 

are $311 billion, or 1.6 percent of GDP. Redemption of trust fund bonds, 

1 This difference is projected on a cash rather than the incurred expenditures basis applied elsewhere 

in the long-range projections, except where explicitly noted otherwise.
8

interest paid on those bonds, and general revenue transfers provide no 

new net income to the Treasury. When the unified budget is not in surplus, 

these payments are made through some combination of increased taxation, reductions in other government spending, or additional borrowing 

from the public.

Each of these trust funds’ operations will contribute increasing amounts 

to Federal unified budget deficits in future years as trust fund bonds are 

redeemed. Until 2029, interest earnings and asset redemptions, financed 

from general revenues, will cover the shortfall of HI tax and premium 

revenues relative to expenditures. In addition, general revenues must 

cover similar payments as a result of growing OASDI bond redemption 

and interest payments through 2034 as the trust fund is drawn down.

If full benefits are to be maintained for both Social Security and Medicare, by 2040 the combined OASDI and HI financing gap plus SMI’s projected general revenue demands will equal 4.2 percent of GDP—more 

than double the 2017 share.

What Is the Outlook for Short-Term Trust Fund Adequacy? The 

reports measure the short-range adequacy of the OASI, DI, and HI Trust 

Funds by comparing fund asset reserves at the start of a year to projected 

costs for the ensuing year (the “trust fund ratio”). A trust fund ratio of 100 

percent or more—that is, asset reserves at least equal to projected cost for 

 Chart D–Projected SMI General Revenue Funding

plus OASDI and HI Tax Shortfalls

[Percentage of GDP]

0%

1%

2%

3%

4%

5%

2017 2020 2023 2026 2029 2032 2035 2038

Calendar year

SMI (B&D)

HI

OASDI
9

the year—is a good indicator of a fund’s short-range adequacy. That level 

of projected reserves for any year suggests that even if cost exceeds 

income, the trust fund reserves, combined with annual tax revenues, 

would be sufficient to pay full benefits for several years. Chart E shows 

the trust fund ratios through 2040 under the intermediate assumptions.

By this measure, the OASI Trust Fund is financially adequate throughout 

and beyond the short-range period (2017-26), but the DI Trust Fund fails 

the short-range test because its trust fund ratio was 31 percent at the 

beginning of 2017 and is not projected to reach 100 percent within 5 

years. The Trustees project that the DI Trust Fund ratio will increase to 

65 percent at the start of 2019, due largely to the temporary payroll tax 

reallocation enacted in the Bipartisan Budget Act of 2015, and subsequently decline until depletion of all reserves in 2028.

The HI Trust Fund does not meet the short-range test of financial adequacy; its trust fund ratio was 67 percent at the beginning of 2017 based 

on the year’s anticipated expenditures, and the projected ratio does not 

rise to 100 percent within five years. Projected HI Trust Fund asset 

reserves become fully depleted in 2029.

The Trustees apply a less stringent annual “contingency reserve” test to 

SMI Part B asset reserves because (i) the financing for that account is set 

each year to meet expected costs, and (ii) the overwhelming portion of the 

financing for that account consists of general revenue transfers and bene-

 Chart E–OASI, DI, and HI Trust Fund Ratios

[Asset reserves as a percentage of annual cost]





















       

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2$6,

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+,

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10

ficiary premiums, which were 75 percent and 23 percent of total Part B 

income in calendar year 2016. Part D premiums paid by enrollees and the 

required amount of general revenue financing are determined each year. 

Moreover, flexible appropriation authority established by lawmakers for 

Part D allows additional general revenue transfers if costs are higher than 

anticipated, limiting the need for a contingency reserve in that account.

What Are Key Dates in OASI, DI, and HI Financing? The 2017 

reports project that the OASI, DI, and HI Trust Funds will all be depleted 

within 20 years. The following table shows key dates for the respective 

trust funds as well as for the combined OASDI trust funds.1

DI Trust Fund reserves will increase until 2019 and then fall steadily until 

they are fully depleted in 2028. Payment of full DI benefits beyond 2028, 

when tax income would cover only 93 percent of scheduled benefits, will 

require legislation to address the financial imbalance. 

The OASI Trust Fund, when considered separately, has a projected 

reserve depletion date of 2035, the same as in last year’s report. At that 

time, income would be sufficient to pay 75 percent of scheduled OASI 

benefits.

The combined OASDI trust funds have a projected depletion date of 

2034, the same as in last year’s report. After the depletion of reserves, 

continuing tax income would be sufficient to pay 77 percent of scheduled 

benefits in 2034 and 73 percent in 2091.

The OASDI reserves are projected to grow in 2017 because total income 

($1,014 billion) will exceed total cost ($955 billion). This year’s report 

indicates that annual OASDI income, including payments of interest to 

the trust funds from the General Fund, will continue to exceed annual cost 

every year until 2022, increasing the nominal value of combined OASDI 

trust fund asset reserves. Social Security’s cost is projected to exceed its 

non-interest income by $27 billion in 2017, and annual non-interest 

income deficits will persist through 2091. The trust fund ratio (the ratio of 

projected reserves to annual cost) will continue to decline gradually 

(Chart E), as it has since 2008, despite this nominal balance increase. 

Beginning in 2022, net redemptions of trust fund asset reserves with GenTable 4: KEY DATES FOR THE TRUST FUNDS 

OASI DI OASDI HI

First year cost exceeds income 

excluding interesta. . . . . . . . . . . . . . . . . . . 

a Dates indicate the first year a condition is projected to occur and to persist annually thereafter through 

2091.

2010 2019 2010 2021

First year cost exceeds total incomea . . . . 2022 2019 2022 2023

Year trust fund reserves are depleted . . . . 2035 2028 2034 2029

1 HI results in this section of the Summary are on a cash rather than the incurred expenditures basis.
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eral Fund payments will be required until projected depletion of these 

reserves in 2034.

The projected HI Trust Fund depletion date is 2029, one year later than in 

last year’s report. Under current law, scheduled HI tax and premium 

income would be sufficient to pay 88 percent of estimated HI cost after 

trust fund depletion in 2029, declining to 81 percent by 2041, and then 

gradually increasing to 88 percent again by 2091.

This report projects that HI Trust Fund reserve assets will increase in 

2017 because total income ($306 billion) will exceed total cost 

($295 billion). Beginning in 2021, projected annual HI cost exceeds noninterest HI income for the remainder of the long-range projection period. 

After 2022, assets will decline continuously until depletion of all reserves 

in 2029. 

What Is the Long-Range Actuarial Balance of the OASI, DI, and HI 

Trust Funds? Another way to view the outlook for payroll tax-financed 

trust funds (OASI, DI, and HI) is to consider their actuarial balances for 

the 75-year valuation period. The actuarial balance measure includes the 

trust fund asset reserves at the beginning of the period, an ending fund 

balance equal to the 76th year’s costs, and projected costs and income 

during the valuation period, all expressed as a percentage of taxable payroll for the 75-year projection period. Actuarial balance is not an informative concept for the SMI program because Federal law sets premium 

increases and general revenue transfers at the levels necessary to bring 

SMI into annual balance.

The actuarial deficit represents the average amount of change in income 

or cost that is needed throughout the valuation period in order to achieve 

actuarial balance. The actuarial balance equals zero if cost for the period 

can be met for the period as a whole and trust fund asset reserves at the 

end of the period are equal to the following year’s cost. The OASI, DI, 

and HI Trust Funds all have long-range actuarial deficits under the intermediate assumptions, as shown in the following table. 

Note: Totals do not necessarily equal the sums of rounded components.

The Trustees project that the annual deficits for Social Security as a 

whole, expressed as the difference between the cost rate and income rate 

for a particular year, will be smaller than the 2016 value (0.79 percent of 

taxable payroll) during 2017-19. The annual deficits then increase 

steadily to 3.77 percent in 2037. Annual deficits then decline gradually to 

Table 5: LONG-RANGE ACTUARIAL DEFICIT OF THE 

OASI, DI, AND HI TRUST FUNDS

[Percent of taxable payroll]

OASI DI OASDI HI

Actuarial

Deficit . . . . . . . . . . . . . . . . . . 2.59 0.24 2.83 0.64
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3.32 percent in 2051 before resuming an upward trajectory and reaching 

4.48 percent of taxable payroll in 2091 (Chart B). The relatively large 

variation in annual deficits indicates that a single tax rate increase for all 

years starting in 2017 sufficient to achieve actuarial balance would result 

in sizable annual surpluses early in the period followed by increasing 

deficits in later years. Sustainable solvency would require payroll tax rate 

increases or benefit reductions (or a combination thereof) by the end of 

the period that are substantially larger than those needed on average for 

this report’s long-range period (2017-91).

In 2016, the HI cost rate exceeded the income rate by 0.03 percent of taxable payroll. The Trustees project that the continued recovery from the 

2007-09 recession and recently enacted legislation, including the ACA, 

will produce small surpluses in 2017 through 2020. Deficits subsequently 

grow rapidly with the aging of the baby boom population through about 

2045, when the annual deficit reaches a peak of 0.93 percent of taxable 

payroll. Annual deficits then decline gradually to 0.60 percent of taxable 

payroll by 2091.

The financial outlooks for both OASDI and HI depend on a number of 

demographic and economic assumptions. Nevertheless, the actuarial deficit in each of these programs is large enough that averting trust fund 

depletion under current-law financing is extremely unlikely. An analysis 

that allows plausible random variations around the intermediate assumptions employed in the report indicates that OASDI trust fund depletion is 

highly probable by mid-century.

How Has the Financial Outlook for Social Security and Medicare 

Changed Since Last Year? Under the intermediate assumptions, the 

combined OASDI trust funds have a projected 75-year actuarial deficit 

equal to 2.83 percent of taxable payroll, 0.17 percentage point larger than 

last year’s estimate. The projected depletion date for the combined asset 

reserves remains 2034. Advancing the valuation date by one year to 

include 2091, a year with a large negative balance, alone accounts for a 

0.05 percentage point increase in the deficit. Changes in assumptions and 

projection methods account for the remaining 0.12 percentage point 

increase.

Medicare’s HI Trust Fund has a long-range actuarial deficit equal to 

0.64 percent of taxable payroll under the intermediate assumptions, 

0.09 percentage point smaller than reported last year. This change was 

primarily due to lower spending in 2016 than anticipated in last year’s 

report and lower projected utilization of inpatient hospital services than 

previously estimated. The anticipated date of depletion of the HI Trust 

Fund is now 2029, a year later than stated in last year’s report.

How Are Social Security and Medicare Financed? For OASDI and HI, 

the major source of financing is payroll taxes on earnings paid by employees and their employers. Self-employed workers pay the equivalent of the 
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combined employer and employee tax rates. During 2016, an estimated 

170.8 million people had earnings covered by Social Security and paid 

payroll taxes; for Medicare the corresponding figure was 174.8 million. 

Current law establishes payroll tax rates for OASDI, which apply to earnings up to an annual maximum ($127,200 in 2017) that ordinarily 

increases with the growth in the nationwide average wage. In contrast to 

OASDI, covered workers pay HI taxes on total earnings. The scheduled 

payroll tax rates (in percent) for 2017 are: 

Self-employed persons pay the combined rates. The Bipartisan Budget 

Act of 2015 reallocated OASDI payroll tax rates on a temporary basis. 

For earnings in calendar years 2016-18, 0.57 percentage point of the 

12.40 percent OASDI payroll tax rate is shifted from OASI to DI. The 

Affordable Care Act applies an additional HI tax equal to 0.9 percent of 

earnings over $200,000 for individual tax return filers, and on earnings 

over $250,000 for joint return filers.

Taxation of Social Security benefits is another source of income for the 

Social Security and Medicare trust funds. Beneficiaries with incomes 

above $25,000 for individuals (or $32,000 for married couples filing 

jointly) pay income taxes on up to 50 percent of their benefits, with the 

revenues going to the OASDI trust funds. This income from taxation of 

benefits made up about 3 percent of Social Security’s income in 2016. 

Those with incomes above $34,000 (or $44,000 for married couples filing 

jointly) pay income taxes on up to 85 percent of benefits, with the 

additional revenues going to the Medicare trust fund. This income from 

taxation of benefits made up about 8 percent of HI Trust Fund income in 

2016.

The trust funds also receive income from interest on their accumulated 

reserves, which are invested in U.S. Government securities. In 2016, 

interest income made up 9 percent of total income to the OASDI trust 

funds, 3 percent for HI, and less than 1 percent for SMI.

Payments from the General Fund financed about 81 percent of SMI 

Part B and Part D costs in 2016, with most of the remaining costs covered 

by monthly premiums charged to enrollees or in the case of low-income 

beneficiaries, paid on their behalf by Medicaid for Part B and Medicare 

for Part D. Part B and Part D premium amounts are determined by methods defined in law and increase as the estimated costs of those programs 

rise. 

Table 6: 2017 PAYROLL TAX RATES

[In percent]

OASI DI OASDI HI Total

Employees . . . . . . 5.015 1.185 6.20 1.45 7.65

Employers . . . . . . 5.015 1.185 6.20 1.45 7.65

Combined total. . . 10.030 2.370 12.40 2.90 15.30
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In 2017, the Part B standard monthly premium is $134.00, $12.20 higher 

than the 2016 amount.1 There are also income-related premium surcharges for Part B beneficiaries whose modified adjusted gross income 

exceeds a specified threshold. In 2017 through 2019, the threshold is 

$85,000 for individual tax return filers and $170,000 for joint return filers. Income-related premiums range from $187.50 to $428.60 per month 

in 2017.

In 2017, the Part D “base monthly premium” is $35.63. Actual premium 

amounts charged to Part D beneficiaries depend on the specific plan they 

have selected and average around $35 for standard coverage. Part D 

enrollees with incomes exceeding the thresholds established for Part B 

must pay income-related monthly adjustment amounts in addition to their 

normal plan premium. For 2017, the adjustments range from $13.30 to 

$76.20 per month. Part D also receives payments from States that partially compensate for the Federal assumption of Medicaid responsibilities 

for prescription drug costs for individuals eligible for both Medicare and 

Medicaid. In 2017, State payments cover about 12 percent of Part D costs.

Who Are the Trustees? There are six Trustees, four of whom serve by 

virtue of their positions in the Federal Government: the Secretary of the 

Treasury, the Secretary of Labor, the Secretary of Health and Human Services, and the Commissioner of Social Security. The other two Trustees 

are public representatives appointed by the President, subject to confirmation by the Senate. The two Public Trustee positions are currently vacant.

1 Because there was a small (0.3 percent) COLA for Social Security in 2017, about 70 percent of SMI 

Part B enrollees have their premium increases limited to an average of about $4.00. In order to limit 

the premium increases for those not held harmless, the financing for 2017 was set to target a contingency reserve below the minimally acceptable level. The Trustees anticipate that for 2018 and later, 

financing will be adjusted to maintain an adequate contingency reserve.
Because the two Public Trustee positions are currently vacant, there is no 

Message from the Public Trustees for inclusion in the Summary of the 

2017 Annual Reports.




.

2017