Connecticut Nexus Combined Base Tax Calculation

Nexus Combined Base Tax Calculation
Form CT-1120CU-NCBForm CT-1120CU-NCB
(Rev. 12/23)
Page 1 of 4
CUNCB 1223W 01 9999

2023

Form CT-1120CU-NCB
Nexus Combined Base
Tax Calculation

Connecticut Designated Taxable Member’s
Connecticut Tax Registration Number

PART I

Nexus Combined Total
1. Form CT‑1120, Schedule D, Line 1 (federal taxable income (loss) before net operating loss and special deductions)

2. Interest income wholly exempt from federal tax ...................................................................................................... 2.

Adjustment for Connecticut Tax Base

3. State and local income taxes ................................................................................................................................... 3.

A
D
D

4. Interest expenses paid to a related member from Form CT‑1120AB, Part I A, Line 1 ...........................................

5. Intangible expenses and costs paid to a related member from Form CT‑1120AB, Part I B, Line 3 ......................

6. Federal bonus depreciation: See instructions. ........................................................................................................ 6.
7. Business interest expense carried forward under IRC § 163(j) and deducted for federal tax purposes in the current year. See instructions. 7.
8. 80% of IRC § 179 deduction. See instructions. ....................................................................................................... 8.
9. Other: Attach explanation. ....................................................................................................................................... 9.
10. Total: Add Lines 1 through 9. .................................................................................................................................. 10.
11a. Dividends from domestic companies less than 20% owned Limited to 70% deduction (less related expenses) .... 11a.
11b. Other dividends (less related expenses) .................................................................................................................11b.
11c. Dividends from a captive REIT taxable in Connecticut ............................................................................................11c.
11d. Intercorporate dividends from corporations included in this combined return ......................................................... 11d.

D
E
D
U
C
T

12. Capital loss carryover (if not deducted in computing federal capital gain): Attach schedule. .................................. 12.
13. Capital gain from sale of preserved land ................................................................................................................. 13.
14. Federal bonus depreciation recovery from Form CT‑1120 ATT, Schedule J, Line 26 ............................................ 14.
15. Exceptions to interest add back from Form CT‑1120AB, Part II A, Line 1 .............................................................. 15.
16. Exceptions to interest add back from Form CT‑1120AB, Part II A, Line 2 .............................................................. 16.
17. Exceptions to interest add back from Form CT‑1120AB, Part II A, Line 3 .............................................................. 17.
18. Exceptions to add back of intangible expenses paid to a related member from Form CT‑1120AB, Part II B, Line 1 18.
19. 25% of IRC § 179 deduction added back in the preceding four years. ................................................................... 19.
20. IRC § 163(j) business interest deduction disallowed for federal tax purposes. See instructions. ........................... 20.
21. Contributions from Connecticut or its municipalities included in Part I, Line 1 above ............................................ 21.
21a. Ordinary and necessary business expenses for taxpayers licensed under Chapter 420f or 420h that are not
claimed for federal income tax purposes. ................................................................................................................. 21a.

Computation of Nexus
Combined Net Income

22. Other: Attach explanation. ....................................................................................................................................... 22.
23. Total: Add Lines 11a through 22. ............................................................................................................................ 23.
24. Net income (loss): Subtract Line 23 from Line 10. If 100% Connecticut, enter also on Line 26. ........................ 24.
25. Apportionment fraction. See instructions. Carry to six places. ................................................................................ 25.
.00

27. Operating loss carryover from separate return year: Cannot exceed 50% of amount on Line 26. Attach schedule. 27. 

.00

28. Net income: Subtract Line 27 from Line 26. ............................................................................................................ 28. 

.00

29. Nexus combined operating loss carryover. Cannot exceed 50% of the amount on Line 28, and the sum of Line 27
and Line 29 cannot exceed 50% of the amount on the Nexus Combined Total column, Line 26. Attach schedule. 29. 

.00

30. Nexus combined income subject to tax: Subtract Line 29 from Line 28. ................................................................. 30. 

.00

PART II 31. Tax: Multiply Line 30 by 7.5% (.075). Enter here and on Form CT‑1120CU‑NCB, Part III, Line 1. ......................... 31. 
1. Form CT‑1120, Schedule E, Line 6, Column C. If 100% Connecticut, enter also on Line 3. See instructions.
1.

.00

Computation of Nexus
Combined Minimum
Tax Base

26. Connecticut net income: Line 24, or Line 24 multiplied by Line 25. ........................................................................ 26. 

2. Apportionment fraction. See instructions. Carry to six places. ................................................................................ 2.
3. Line 1, or Line 1 multiplied by Line 2. ...................................................................................................................... 3.
4. Number of months covered by this return ............................................................................................................... 4.
5. Line 3 multiplied by Line 4, divide by 12. ................................................................................................................. 5.
6. Nexus combined minimum tax base: Add all amounts on Line 5. ........................................................................... 6. 

.00

7. Tax: Multiply Line 6 by 0.0031 (31/10 mils per dollar). Maximum $1,000,000. Enter here and on Form CT‑1120CU‑NCB, Part III, Line 2.

.00

Visit us at portal.ct.gov/DRS for more information.

7. 

Form CT-1120CU-NCB
(Rev. 12/23)
Page 2 of 4
CUNCB 1223W 02 9999

Column A
Taxable
Member #:

Connecticut Designated Taxable Member’s
Connecticut Tax Registration Number

Column B
Taxable
Member #:

(A. = Enter corporation name)
Column C
Taxable
Member #:

Column D
Taxable
Member #:

Column E
Taxable
Member #:

A.
1.

.00

7.
8.

.00

10.

.00

11a.

.00

11b.

.00

11c.

.00

11d.

.00

12.

.00

13.

.00

14.

.00

15.

.00

16.

.00

17.

.00

18.

.00

19.

.00

20.

.00

21.

.00

21a.

.00

22.

.00

23.

.00

24.
25.

.00

.00
.00

.00

26.

.00

27.

.00

.00
.00

28.

.00

29.
30.
31.
1.
2.

.00

6.
7.

Visit us at portal.ct.gov/DRS for more information.

.00

Form CT-1120CU-NCB
(Rev. 12/23)
Page 3 of 4
CUNCB 1223W 03 9999

Connecticut Designated Taxable Member’s
Connecticut Tax Registration Number

PART III – Aggregate Maximum Tax
1. Tax on nexus combined net income from Part I, Line 31, Nexus Combined Total column. ....................... 1.

.00

2. Tax on nexus combined minimum tax base from Part II, Line 7, Nexus Combined Total column. ............. 2.

.00

3. Enter the larger of Line 1 or Line 2, Nexus Combined Tax. ......................................................................... 3.

.00

4. Maximum addition amount. ........................................................................................................................ 4.

2,500,000 .00

5. Aggregate Maximum Tax: Add Line 3 and Line 4. Enter here and on Form CT‑1120CU, Part I, Line 4. ... 5.

.00

Column A
Taxable
Member #:

Allocation of Aggregate Maximum Tax

Column B
Taxable
Member #:

Column C
Taxable
Member #:

Corporation name:

6. Enter in each column the tax reported

for each taxable member on Form
CT‑1120CU‑NI, Part III, Line 13. ................................................ 6.

7. Enter the amount reported on Form

CT‑1120CU‑NI, Part III, Line 14. ............... 7.

8. Divide the amount in each column on

Line 6 by Line 7. ......................................................................... 8.

.00

9. Allocation of aggregate maximum tax:

Multiply the amount on Line 5 by the percentage
reported on Line 8 in each column. Enter
also in each corresponding column on Form
CT‑1120CU, Part I, Line 6c. ............................................................. 9.

.00

Visit us at portal.ct.gov/DRS for more information.

.00

Form CT-1120CU-NCB
(Rev. 12/23)
Page 4 of 4
CUNCB 1223W 04 9999

Column D
Taxable
Member #:

Connecticut Designated Taxable Member’s
Connecticut Tax Registration Number

Column E
Taxable
Member #:

(A. = Enter corporation name)
Column F
Taxable
Member #:

Column G
Taxable
Member #:

Column H
Taxable
Member #:

.00

7.
8.

.00

Visit us at portal.ct.gov/DRS for more information.

.00

Form CT-1120CU-NCB Instructions
Do not complete this form if Form CT‑1120CU, Part I,
Line 3 is less than or equal to $2,500,000.

Purpose

Line 1

Enter the corporation’s federal taxable income (loss) before
net operating loss and special deductions as filed on the
taxable member’s federal return.

If the amount reported on Form CT‑1120CU, Part I, Line 3
is greater than $2,500,000, use Form CT‑1120CU‑NCB
to calculate whether the combined group’s tax liability is
capped at an amount less than would otherwise be due on
the standard combined unitary basis. If applicable, complete
and attach Form CT‑1120CU‑NCB to Form CT‑1120CU. See
Special Notice 2016(1), Combined Unitary Legislation.

Line 2

Nexus Combined Base

Line 4

A combined group’s tax liability, prior to surtax and credits,
cannot exceed the amount calculated on a nexus combined
basis by more than $2,500,000. This is referred to as the
aggregate maximum tax. If the aggregate maximum tax (as
calculated on this form) is less than the tax on the standard
combined unitary basis (as reported on Form CT‑1120CU,
Part I, Line 3), the group is subject to the aggregate maximum
tax. Otherwise, the group is subject to tax on the standard
combined unitary basis.
If the combined group determines that the calculations on
Form CT‑1120CU‑NCB do not affect the tax due, it is not
required to file this form (even if Part I, Line 3 is greater
than $2,500,000). If the combined group later determines
that the calculations do impact the tax due, it may file Form
CT‑1120CU‑NCB with an amended return or provide Form
CT‑1120CU‑NCB to DRS during the course of an audit
examination.
See Special Notice 2016(1), Combined Unitary Legislation.

Part I – Computation of Nexus Combined Net
Income

Nexus combined net income is the sum of the apportioned
separate net income or loss of each taxable member
included in the combined unitary return. For nexus
combined purposes, each taxable member calculates
its apportioned net income as if it were filing a separate
return, subject to certain adjustments specific to the
nexus combined base.
Net Income Adjustments. Any intercompany intangible
expenses and costs required to be added back pursuant to
Conn. Gen. Stat. § 12‑218c and the corresponding income
attributable to such expenses are eliminated provided
that both the payor and payee are both taxable members
included in the combined unitary return. See Conn. Gen.
Stat. § 12‑218e(k)(2)(B). Enter the amount of expenses or
income to be eliminated on Line 9 and Line 22, respectively.
Intercorporate dividends from taxable members included
in this combined unitary return are deducted. See Conn.
Gen. Stat. § 12‑218e(k)(2)(A).
Net Income Apportionment Calculation Adjustment.
Do not include receipts from any other taxable member
included in this combined unitary return in the computation
of the receipts factor of the apportionment fraction.
Calculate each taxable member’s apportioned net income
on the consolidating schedules. Enter the sum of Lines 26
through 28 of each included corporation in the Nexus
Combined Total column.
Form CT-1120CU-NCB Instructions (Rev. 12/23)

Enter all interest income exempt from federal taxation.

Line 3

Enter state and local income taxes deducted in the calculation
of federal taxable income, including Connecticut Corporation
Business Tax.
Enter the amount of interest expenses paid to a related
member as reported on Form CT‑1120AB, Part I A, Line 1.

Line 5

Enter the amount of intangible expenses paid to a related
member as reported on Form CT‑1120AB, Part I B, Line 3.

Line 6

Enter the amount of the federal bonus depreciation allowed
under IRC § 168(k) and claimed on federal Form 4562,
Depreciation and Amortization.

Line 7

Enter the amount of business interest expense that was
incurred in a prior year and that was carried forward and
deducted in the current year for federal tax purposes pursuant
to IRC § 163(j).

Line 8

Enter 80% of the IRC § 179 deduction claimed for federal
tax purposes.

Line 9

Enter any other income amount. Attach an explanation.
Include the amount of intercompany intangible expenses
and costs that are eliminated pursuant to Conn. Gen. Stat.
§ 12‑218e(k)(2)(B).

Line 11a

Enter the amount entered on Form CT‑1120 ATT, Schedule I,
Line 2.

Line 11b

Enter the amount entered on Form CT‑1120 ATT, Schedule I,
Line 3.

Line 11c

Enter the amount entered on Form CT‑1120 ATT, Schedule I,
Line 4.

Line 11d

Enter the amount of intercorporate dividends from taxable
members included in this combined unitary return not
otherwise deducted.

Line 12

Enter the amount of any available capital loss carryover not
deducted in computing federal capital gain. This amount is
limited to the amount of the capital gain reported on the federal
return as described in Conn. Gen. Stat. § 12‑217.
Page 1 of 3

Line 13

Enter the value of any capital gain realized from the sale of any
land, or interest in land, to the state, any political subdivision
of the state, or to any nonprofit land conservation organization
where such land is to be permanently preserved as protected
open space or to a water company (as defined in Conn.
Gen. Stat. § 25‑32a), where such land is to be permanently
preserved as protected open space land or as Class I or
Class II water company land.

Line 14

Enter the federal bonus depreciation recovery amount from
Form CT‑1120 ATT, Schedule J, Line 26.

Line 15

Enter the amount of exceptions to interest add back as
reported on Form CT‑1120AB, Part II A, Line 1.

Line 16

Enter the amount of exceptions to interest add back as
reported on Form CT‑1120AB, Part II A, Line 2.

Line 17

Enter the amount of exceptions to interest add back as
reported on Form CT‑1120AB, Part II A, Line 3.

Line 18

Enter the amount of exceptions to the add back of intangible
expenses paid to a related member as reported on Form
CT‑1120AB, Part II B, Line 1.

Line 19

Enter 25% of IRC § 179 deduction that was added back
in calculating the Connecticut net income in the preceding
four years.

Line 20

Enter the amount of business interest expense that was
incurred in the current year but was not allowed to be deducted
for federal tax purposes pursuant to IRC § 163(j).

Line 21

Enter the amount of any contributions made by the State of
Connecticut or political subdivision thereof to the extent those
contributions are included in federal taxable income.

Line 21a

For corporations that are licensed under Chapter 420f or 420h of
the Connecticut General Statutes, enter the amount of ordinary
and necessary business expenses allowed under IRC § 162 in
determining the Connecticut corporation business tax liability.

Line 22

Enter any other income deduction. Attach an explanation.
• Enter the Foreign Derived Intangible Income (FDII)
deduction claimed for federal purposes.
• Enter the amount of income received from a taxable
member included in the combined unitary return attributable
to intangible expenses and costs that is eliminated
pursuant to Conn. Gen. Stat. § 12‑218e(k)(2)(B).
• Enter the amount received from a related member
attributable to intangible expenses and costs (that is not
already eliminated on this line) or to interest expenses
and costs, provided such income was:
1. Included on Part I, Line 1 of this return;
Form CT-1120CU-NCB Instructions (Rev. 12/23)

2. Received from a related member who filed a
Connecticut Corporation Business Tax return for
the same income year (other than as a nontaxable
member of a combined unitary return); and
3. Required to be added back by the related member
under Conn. Gen. Stat. §§ 12‑218c or 12‑218d and
was not entitled to an exception of the add back.

Line 24

Subtract Line 23 from Line 10. Enter the result here.

Line 25

Enter the apportionment fraction from Form CT‑1120A,
Schedule Q, or from the appropriate apportionment form.
The fraction must be expressed as a decimal and carried to
six places.

Line 26

Enter the amount from Line 24 multiplied by Line 25, or enter
the amount from Line 24, if not entitled to apportion.

Line 27 and Line 29

For purposes of calculating the nexus combined tax, net
operating losses (NOLs) incurred in a prior year by a taxable
member or by a group that included a taxable member
may be utilized to offset net income reported on this form.
NOLs that may be utilized include NOLs reported on Form
CT‑1120, Form CT-1120CR, Form CT-1120U, or NOLs
reported in the calculation of the nexus combined tax on
Form CT-1120CU-NCB. NOLs reported in the calculation of
the nexus combined base tax on Form CT-1120CU-NCB and
NOLs reported on a Form CT-1120 or Form CT‑1120CR may
be utilized in a manner consistent with the rules prescribed
by Conn. Agencies Regs. § 12‑223a-2. NOLs reported on a
Form CT-1120U may be utilized by any taxable member that
filed as part of such return in the year of the loss.
NOL from a Form CT-1120. NOLs reported in a prior year
on a Form CT-1120 may only be used to offset the income
of the taxable member that generated the loss. Such NOLs
should be reported on Line 27 and may not exceed 50% of
each taxable member’s separately calculated net income.
NOL from a Form CT-1120CR, Form CT-1120U or Form
CT-1120CU-NCB. NOLs reported in a prior year on a Form
CT‑1120CR, Form CT‑1120U or Form CT‑1120CU‑NCB
that may be used to offset the income of more than one
taxable member should be reported on Line 29.
The total amount of NOL applied on Line 27 and Line 29
cannot exceed 50% of net income reported on the Nexus
Combined Total column, Line 26.

Part II – Computation of Nexus Combined
Minimum Tax Base

The nexus combined minimum tax base is the sum of the
separate minimum tax base of each taxable member included
in the combined unitary return, but only to the extent the base
is separately apportioned to Connecticut in accordance with
the provisions of Conn. Gen. Stat. §§ 12-219a or 12‑244.
If any income or expenses are eliminated in Part I, Line 22,
the intangible property of the taxable member eliminating the
income shall not be taken into account in apportioning the
minimum tax base.
The maximum tax for the nexus combined minimum tax base
is $1,000,000.
Page 2 of 3

Part III – Aggregate Maximum Tax
Line 1

Enter the amount from Part I, Line 31, Nexus Combined Total
column.

Line 2

Enter the amount from Part II, Line 7, Nexus Combined Total
column.

Line 3

Allocation of Aggregate Maximum Tax

This section is used to allocate the aggregate maximum tax
among the taxable members of the group.

Line 6

Enter in each column the tax reported for each taxable
member on Form CT‑1120CU‑NI, Part III, Line 13.

Line 7

Enter the greater of Line 1 or Line 2.

Enter the amount reported on Form CT‑1120CU‑NI, Part III,
Line 14.

Line 5

Line 8

Add $2,500,000 to the amount reported on Line 3. This
represents the combined group’s aggregate maximum tax.
Enter this amount here and on Form CT‑1120CU, Part I,
Line 4.

Form CT-1120CU-NCB Instructions (Rev. 12/23)

Divide the amount in each column on Line 6 by the amount
on Line 7.

Line 9

Multiply the amount on Line 5 in this Part by the percentage
reported on Line 8 in each column. Also, enter these amounts
in each corresponding column on Form CT‑1120CU, Part I,
Line 6c.

Page 3 of 3

Extracted from PDF file 2023-connecticut-form-ct-1120cu-ncb.pdf, last modified December 2023

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More about the Connecticut Form CT-1120CU-NCB Corporate Income Tax TY 2023

We last updated the Nexus Combined Base Tax Calculation in February 2024, so this is the latest version of Form CT-1120CU-NCB, fully updated for tax year 2023. You can download or print current or past-year PDFs of Form CT-1120CU-NCB directly from TaxFormFinder. You can print other Connecticut tax forms here.

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Related Connecticut Corporate Income Tax Forms:

TaxFormFinder has an additional 85 Connecticut income tax forms that you may need, plus all federal income tax forms. These related forms may also be needed with the Connecticut Form CT-1120CU-NCB.

Form Code	Form Name
Form CT-1120CU-MI	Combined Group Member Information
Form CT-1120CU-MTB	Tax on Combined Group Minimum Tax Base
Form CT-1120CU-NI	Tax on Combined Group Net Income

Download all CT tax forms View all 86 Connecticut Income Tax Forms

Form Sources:

Connecticut usually releases forms for the current tax year between January and April. We last updated Connecticut Form CT-1120CU-NCB from the Department of Revenue Services in February 2024.

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About the Corporate Income Tax

The IRS and most states require corporations to file an income tax return, with the exact filing requirements depending on the type of company.

Sole proprietorships or disregarded entities like LLCs are filed on Schedule C (or the state equivalent) of the owner's personal income tax return, flow-through entities like S Corporations or Partnerships are generally required to file an informational return equivilent to the IRS Form 1120S or Form 1065, and full corporations must file the equivalent of federal Form 1120 (and, unlike flow-through corporations, are often subject to a corporate tax liability).

Additional forms are available for a wide variety of specific entities and transactions including fiduciaries, nonprofits, and companies involved in other specific types of business.

Historical Past-Year Versions of Connecticut Form CT-1120CU-NCB

We have a total of four past-year versions of Form CT-1120CU-NCB in the TaxFormFinder archives, including for the previous tax year. Download past year versions of this tax form as PDFs here:

2023 Form CT-1120CU-NCB

2022 Form CT-1120CU-NCB

2021 Form CT-1120CU-NCB

2020 Form CT-1120CU-NCB

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Connecticut Nexus Combined Base Tax Calculation

Nexus Combined Base Tax CalculationForm CT-1120CU-NCB

More about the Connecticut Form CT-1120CU-NCB Corporate Income Tax TY 2023

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Related Connecticut Corporate Income Tax Forms:

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Historical Past-Year Versions of Connecticut Form CT-1120CU-NCB

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Nexus Combined Base Tax Calculation
Form CT-1120CU-NCB