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Update on the Revenue Effects of GILTI and FDII, 2026 Rate Changes, and Proposed Policy Reforms

Summary: We analyze new data from the US Treasury to examine historical revenue effects of TCJA’s international corporate tax provisions. We also provide updated conventional estimates to assess the revenue impact of scheduled 2026 rate increases on foreign income of US corporations and assess several proposals that aim to further increase tax revenue.

Key Points

  • Since TCJA’s implementation, multinationals have significantly increased their use of the FDII tax incentive. PWBM estimates that, between 2018 and 2021, Section 250 deductions for FDII have more than doubled, growing from $69 billion in 2018 to $139 billion in 2021. Section 250 deductions for GILTI have also grown over this period, but at a slower rate, from $171 billion in 2018 to $304 billion in 2021.

  • On a conventional basis, we estimate that scheduled rate increases to FDII and GILTI in 2026 will generate $410 billion in additional revenue by 2035 relative to a scenario in which the pre-2026 rates are extended indefinitely.

  • We analyze several proposals to modify the taxation of GILTI and FDII and find that eliminating the deemed tangible income return exclusion from the GILTI computation would generate $58 billion in revenue by 2035. Eliminating the Section 250 deduction for FDII would generate an additional $363 billion, and cutting the Section 250 deduction rate for GILTI in half would generate an additional $785 billion on a conventional basis.


Update on the Revenue Effects of GILTI and FDII, 2026 Rate Changes, and Proposed Policy Reforms

Introduction

At the end of September, the Treasury Department released a trove of corporate tax data, including its biannual study of the international corporate tax provisions of the 2017 Tax Cuts and Jobs Act (TCJA). This data provides new facts about the taxation of two categories of foreign income created by TCJA, known as Global Intangible Low-Taxed Income (GILTI) and Foreign-Derived Intangible Income (FDII). PWBM has been working to incorporate this new data into its tax module. This brief uses the new Treasury data in conjunction with our updated tax module to provide insight into the historical revenue effects of these provisions and to analyze how upcoming changes to the tax code, scheduled to take effect in 2026, will impact the federal government’s tax receipts. In addition to analyzing these changes, we also provide conventional revenue estimates for a set of proposed policy reforms that aim to increase US tax revenue collected on GILTI and FDII.1

Historical Comparison of GILTI and FDII

Although TCJA took effect in 2018, the US Treasury typically releases data with a lag of several years. The most recent data released by the Treasury in September 2024 provides information covering tax filings for the 2021 tax year.

GILTI includes foreign income of US corporations earned by their foreign affiliates, whereas FDII captures foreign-source income earned directly by a US-domiciled corporation. Both categories of income attempt to proxy for highly mobile income generated by firms’ intangible assets by excluding a “normal” return on investment that depends on the tangible assets of the firm. Since 2018, there has been significant growth in foreign income under the FDII category compared to GILTI, with a surge in FDII deductions between 2020 and 2021. Overall, we estimate that the FDII deduction has more than doubled between 2018 and 2021, growing from $69 billion to $139 billion. Although corporations report relatively more income categorized under GILTI compared to FDII, much of this is offset by a foreign tax credit allowed for a portion of the foreign taxes paid on GILTI. As a result, tax liability on GILTI has been considerably lower than FDII since TCJA’s implementation, as shown in Figure 1. This figure also shows the revenue that would have been collected on FDII if this income were taxed at the full US statutory rate of 21%, without taking into account potential behavioral responses.2

Figure 2 provides another perspective. Although TCJA has collected considerable revenue on income from US-owned foreign affiliates under GILTI, this has largely been offset by the tax incentive on foreign-source income earned by US-domiciled corporations under FDII.

Figure 1: GILTI and FDII Tax Liability

Figure 2: GILTI Liability Net of FDII Tax Incentive

Fiscal Effect of TCJA 2026 Rate Changes

Many provisions of TCJA that affect taxation of individuals are scheduled to expire at the end of 2025. In contrast, TCJA’s corporate tax provisions are largely permanent. However, starting in 2026, there are significant changes to the deduction rates for GILTI and FDII that will increase the effective US tax rate on foreign corporate income. For income categorized under FDII, the effective rate will increase from 13.1% to 16.4%. GILTI, in conjunction with the foreign tax credit, functions as a minimum tax that affects companies facing a foreign effective tax rate that falls below a certain threshold. This minimum tax rate will also increase from 13.1% to 16.4% in 2026.

By 2026, we project that aggregate foreign income will reach about $800 billion in GILTI and $550 billion in FDII. Figure 3 shows the fiscal effect of the 2026 rate changes on a conventional basis. From 2026 to 2035, we estimate these rate increases will generate $410 billion in additional revenue relative to a scenario where the pre-2026 rates are extended indefinitely.

Figure 3: Fiscal Effect of TCJA 2026 Rate Changes

Examining Proposals to Modify GILTI and FDII

There have been numerous proposals aiming to reform the tax code to increase tax revenue on GILTI and FDII. In Figure 4, we analyze three such proposals: (1) eliminating the deemed tangible income return exclusion from the GILTI computation, (2) eliminating the Section 250 deduction for FDII, and (3) reducing the Section 250 deduction for GILTI by half. We conduct a “stacked” estimate, such that these policy reforms are implemented on top of each other, and present the results in terms of the change in revenue generated by each successive reform. We emphasize that conventional estimates will not capture all behavioral responses to these reforms, and that dynamic estimates would likely result in smaller revenue changes. Between 2026 and 2035, we estimate that eliminating the deemed tangible income return exclusion would generate $58 billion in additional revenue, eliminating the Section 250 deduction for FDII would generate $363 billion, and cutting the Section 250 deduction rate for GILTI in half would generate $785 billion.

Revenue Raisers

Figure 4: Fiscal Effect of Possible Revenue Raisers



This analysis was produced by Lysle Boller, Lorraine Luo, and Xiaoyue Sun under the direction of Alex Arnon and the faculty director, Kent Smetters. Mariko Paulson prepared the brief for the website.


  1. We caution readers that the foreign corporate tax base can be highly responsive to changes in the tax code. PWBM has been overhauling its tax module to better capture this responsiveness with plans to release dynamic estimates of international tax policy reforms in the future.  ↩

  2. One would expect firms to shift income from the FDII category to GILTI if the FDII tax incentive were eliminated.  ↩

  Year	name	value
  2018	GILTI Liability	11.75272332
  2018	FDII Liability	24.13831963
  2019	GILTI Liability	18.18817621
  2019	FDII Liability	29.61980648
  2020	GILTI Liability	13.24656472
  2020	FDII Liability	31.40722778
  2021	GILTI Liability	19.51197629
  2021	FDII Liability	48.78917663
  2018	FDII Liability Excluding S250 Deduction (height)	14.48299178
  2018	FDII Liability Excluding S250 Deduction (tooltip)	38.6213114
  2019	FDII Liability Excluding S250 Deduction (height)	17.77188389
  2019	FDII Liability Excluding S250 Deduction (tooltip)	47.39169036
  2020	FDII Liability Excluding S250 Deduction (height)	18.84433667
  2020	FDII Liability Excluding S250 Deduction (tooltip)	50.25156444
  2021	FDII Liability Excluding S250 Deduction (height)	29.27350598
  2021	FDII Liability Excluding S250 Deduction (tooltip)	78.0626826
  Year	name	value
  2018	GILTI Liability	11.75272332
  2018	GILTI Liability Net of FDII Tax Incentive	-2.73026846
  2019	GILTI Liability	18.18817621
  2019	GILTI Liability Net of FDII Tax Incentive	0.41629232
  2020	GILTI Liability	13.24656472
  2020	GILTI Liability Net of FDII Tax Incentive	-5.597771942
  2021	GILTI Liability	19.51197629
  2021	GILTI Liability Net of FDII Tax Incentive	-9.76152969
  year	Change in Liability
  2025	0
  2026	35.82506585
  2027	38.09058737
  2028	38.3076885
  2029	38.43507769
  2030	39.59807714
  2031	41.97328485
  2032	41.8890144
  2033	43.98727257
  2034	44.96390601
  2035	46.83842515
  scenario	year	change_in_Liability
  Eliminate Exclusion for Deemed Tangible Income Return	2025	2.463359847
  Eliminate FDII Deduction	2025	41.71812767
  Halve S250 GILTI Deduction Rate	2025	82.50792117
  Eliminate Exclusion for Deemed Tangible Income Return	2026	4.700324778
  Eliminate FDII Deduction	2026	28.67021756
  Halve S250 GILTI Deduction Rate	2026	60.77149511
  Eliminate Exclusion for Deemed Tangible Income Return	2027	4.995022521
  Eliminate FDII Deduction	2027	30.16939443
  Halve S250 GILTI Deduction Rate	2027	64.63276222
  Eliminate Exclusion for Deemed Tangible Income Return	2028	5.120131469
  Eliminate FDII Deduction	2028	30.24581697
  Halve S250 GILTI Deduction Rate	2028	65.38022749
  Eliminate Exclusion for Deemed Tangible Income Return	2029	5.217804275
  Eliminate FDII Deduction	2029	30.31606369
  Halve S250 GILTI Deduction Rate	2029	65.91977547
  Eliminate Exclusion for Deemed Tangible Income Return	2030	5.393132975
  Eliminate FDII Deduction	2030	31.09163236
  Halve S250 GILTI Deduction Rate	2030	68.02562804
  Eliminate Exclusion for Deemed Tangible Income Return	2031	5.722878038
  Eliminate FDII Deduction	2031	32.78065027
  Halve S250 GILTI Deduction Rate	2031	72.13558139
  Eliminate Exclusion for Deemed Tangible Income Return	2032	5.666095675
  Eliminate FDII Deduction	2032	32.63590732
  Halve S250 GILTI Deduction Rate	2032	71.92859331
  Eliminate Exclusion for Deemed Tangible Income Return	2033	5.976045254
  Eliminate FDII Deduction	2033	34.19489229
  Halve S250 GILTI Deduction Rate	2033	75.61169805
  Eliminate Exclusion for Deemed Tangible Income Return	2034	6.116662555
  Eliminate FDII Deduction	2034	34.8399118
  Halve S250 GILTI Deduction Rate	2034	77.26178532
  Eliminate Exclusion for Deemed Tangible Income Return	2035	6.386854806
  Eliminate FDII Deduction	2035	36.22839602
  Halve S250 GILTI Deduction Rate	2035	80.52650209