Until recently, the DI trust fund was projected to be depleted in the fourth quarter of calendar year 2016, at which time ongoing revenues to the DI trust fund were projected to be sufficient to pay only about 80% of scheduled benefits. 1314 ; P.L. 114-74 ) extended the projected solvency of the DI trust fund by authorizing a reallocation of the Social Security payroll tax rate between the DI and the Old-Age and Survivors Insurance (OASI) trust funds to provide DI with a larger share. In 2014, SSDI provided disability insurance coverage to more than 151 million nonelderly workers. The Federal Disability Insurance Trust Fund finances the benefits of disabled workers and their dependents, and the Federal Old-Age and Survivors Insurance Trust Fund pays for the benefits of retired workers and their dependents as well as survivors of deceased workers. Each trust fund is a separate account in the U.S. Treasury, and under current law, the two trust funds may not borrow from one another. Financing

SSDI and OASI are financed primarily by dedicated payroll and self-employment taxes levied on the earnings of covered workers under the Federal Insurance Contributions Act (FICA) and the Self-Employment Contributions Act (SECA). In other words, up to a certain rate, taxes paid on OASI benefits are deposited in the OASI trust fund and taxes paid on SSDI benefits are deposited in the DI trust fund. Causes of the DI Trust Fund's Financial Imbalance

The declining solvency of the DI trust fund is the result of an increasing imbalance between its income and cost. Over the past 20 years, the annual DI income rate has remained relatively flat at about 1.81% of taxable payroll, which is roughly the combined share of the tax rate allocated to the DI trust fund for that period plus a small amount of other income. The increase in the annual DI cost rate stems largely from the growth in the number of beneficiaries on SSDI. Between 1995 and 2014, the total number of disabled workers and their dependents in receipt of SSDI increased 85%, from 5.9 million to 10.9 million. The Social Security Act provides no guidance on the payment of benefits once a trust fund's asset reserves have been depleted and current tax revenues are insufficient to meet current cost. Although individuals who meet Social Security's eligibility requirements are legally entitled to disability benefits, a provision in the Antideficiency Act prohibits a federal agency from spending in excess of available funds. Because the Social Security Act stipulates that SSDI benefit payments shall be made only from the DI trust fund, without a change in the law, monthly cash payments to beneficiaries could be delayed or reduced if the DI trust fund were depleted. Upon depletion of its asset reserves in late 2016, the trustees projected that continuing tax revenues to the DI trust fund would have been sufficient to pay 81% of SSDI benefits. Under the Bipartisan Budget Act of 2015

On November 2, 2015, President Barack Obama signed into law the Bipartisan Budget Act of 2015 ( H.R. Among its many provisions, the act authorized a temporary reallocation of the Social Security payroll tax rate between the OASI and DI trust funds to provide DI with a larger share for 2016 through 2018. Specifically, the DI trust fund's share of the tax rate for employees and employers, each, increased by 0.285 percentage point at the beginning of 2016, from 0.900% to 1.185% ( Table 4 ). Because the act did not change the Social Security payroll tax rate, the portion of the tax rate allocated to OASI decrease d by a corresponding amount. On a combined basis , OASI's share of the 12.400% tax rate declined by 0.570 percentage point, from 10.600% to 10.030%. For 2019 and later, the shares allocated to the DI and OASI trust funds are scheduled to return to their 2015 levels. SSA's Office of the Chief Actuary (OACT) projects that the reallocation schedule in the Bipartisan Budget Act of 2015 will extend the solvency of the DI trust fund from the fourth quarter of 2016 to approximately the third quarter of 2022 ( Figure 6 ). Although the reallocation is projected to reduce the solvency of the OASI trust fund by a number of months, OACT estimates that the depletion year for OASI will remain unchanged at 2035. For information on reform proposals that would affect the solvency of the DI trust fund (or both trust funds), see the following resources:
CRS Report R43054, Social Security Disability Insurance (SSDI) Reform: An Overview of Proposals to Manage the Growth in the SSDI Rolls , by [author name scrubbed]; CBO's 2012 report, Policy Options for the Social Security Disability Insurance Program , at http://www.cbo.gov/publication/43421 ; CBO's 2015 report, Social Security Policy Options, 2015 , at https://www.cbo.gov/publication/51011 ; OACT's Summary of Provisions That Would Change the Social Security Program , at https://www.ssa.gov/oact/solvency/provisions/summary.pdf ; OACT's collection of cost estimates for various proposals affecting the solvency of the trust funds at https://www.ssa.gov/oact/solvency/index.html ; and the Government Accountability Office's (GAO) 2015 report, Social Security's Future: Answers to Key Questions , at http://www.gao.gov/products/GAO-16-75SP .
Social Security Disability Insurance (SSDI) provides benefits to nonelderly workers and their eligible dependents if the worker paid Social Security taxes for a certain number of years and is unable to perform substantial work due to a qualifying impairment. As in Old-Age and Survivors Insurance (OASI)—the retirement component of Social Security—benefits are based on a worker's past earnings in covered employment. In December 2014, SSDI provided disability insurance coverage to more than 151 million people and paid benefits to about 9 million disabled workers and 2 million of their spouses and children.
Benefits and administrative costs for SSDI and OASI are financed primarily by dedicated payroll and self-employment taxes levied on the earnings of covered workers, which are deposited in the Federal Disability Insurance (DI) Trust Fund and the Federal Old-Age and Survivors Insurance (OASI) Trust Fund, respectively. The combined Social Security tax on earnings is 12.40%, which is split equally between workers and employers (6.20% each). Of that amount, 2.37% is allocated to the DI trust fund and 10.03% is allocated to the OASI trust fund. Each trust fund is a legally distinct account in the U.S. Treasury, and under current law, the two trust funds may not borrow from one another.
Over the past few years, Congress has grown increasingly concerned with the financial outlook of the DI trust fund. Cost has exceeded total income since 2009, causing the balance of the DI trust fund to shrink. In their July 2015 report, the Social Security trustees projected that the DI trust fund would be depleted in the fourth quarter of calendar year 2016. Upon depletion of its asset reserves, the DI trust fund was projected to have enough ongoing revenues to pay only about 80% of scheduled benefits. The trustees projected that the OASI trust fund would be depleted in 2035.
The Social Security Act provides no guidance on the payment of benefits once a trust fund's asset reserves have been depleted and current tax revenues are insufficient to meet current cost. Although individuals who meet Social Security's eligibility requirements are legally entitled to disability benefits, a provision in the Antideficiency Act prohibits a federal agency from spending in excess of available funds. Because the Social Security Act stipulates that SSDI benefit payments shall be made only from the DI trust fund, without a change in the law, monthly cash payments to beneficiaries could be delayed or reduced if the DI trust fund were depleted.
The decreasing solvency of the DI trust fund is the result of an increasing imbalance between the fund's income and cost. Over the past 20 years, tax revenues to the DI trust fund have remained relatively flat as a percentage of taxable payroll, whereas cost as a share of taxable payroll has grown markedly. The increase in cost stems largely from the growth in the number of beneficiaries in the program. Between 1995 and 2014, the number of disabled workers and their dependents in receipt of SSDI grew 85%, from 5.9 million to 10.9 million. Because benefit payments account for nearly all program spending, the growth in the SSDI rolls has contributed heavily to the financial difficulties of the DI trust fund.
On November 2, 2015, President Barack Obama signed into law the Bipartisan Budget Act of 2015 (H.R. 1314; P.L. 114-74). Among its many provisions, the act authorized a temporary reallocation of the Social Security payroll tax rate between the OASI and DI trust funds to provide DI with a larger share for 2016 through 2018. Specifically, the DI trust fund's share of the combined tax rate increased by 0.57 percentage point at the beginning of 2016, from 1.80% to 2.37%. Because the act did not change the combined payroll tax rate of 12.40%, the portion of the tax rate allocated to OASI decreased by a corresponding amount. This means that OASI's share of the combined tax rate declined by 0.57 percentage point at the start of 2016, from 10.60% to 10.03%. For 2019 and later, the shares allocated to the DI and OASI trust funds are scheduled to return to their 2015 levels (i.e., 1.80% to the DI trust fund and 10.60% to the OASI trust fund).
The Social Security Administration's Office of the Chief Actuary (OACT) projects that the reallocation will extend the solvency of the DI trust fund from the fourth quarter of 2016 to the third quarter of 2022. Although the reallocation will reduce the solvency of the OASI trust fund slightly, OACT estimates that the depletion year for OASI will remain unchanged at 2035.