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Federal Tax Law Investigation

On January 3, 2018, the IURC opened an investigation "into the impacts of the Tax Cuts and Jobs Act of 2017 and possible rate implications." The Commission formally closed the investigation in a January 27, 2021 order.

The new federal law reduced the corporate tax rate for most investor-owned utilities from 35 percent to 21 percent. Utilities that pay federal income taxes may recover them through rates on a dollar-for-dollar basis.

The OUCC participated on behalf of Indiana consumers in Cause No. 45032. All rate-regulated, investor-owned utilities were parties to the case. Municipal and not-for-profit utility rates were not at issue.

The investigation had two phases:

  1. Immediate rate relief
  2. Longer term tax issues

Phase One: Immediate Rate Relief

Rates for most Indiana utilities decreased to reflect the federal corporate income tax reduction utilities received on January 1, 2018. More specifically, tariffs were adjusted to reflect the new 21% rate.

Phase Two: Longer Term Tax Issues

The case's second phase examined longer term issues including customer credits for rates collected at the 35-percent tax rate since January 1, 2018 and deferred income tax accounting matters.

Phase Two issues for each utility were addressed in separate subdockets, with links to each case file below. Commission orders have been issued in all subdockets.


Duke Energy: A settlement agreement resolving all issues in both phases received IURC approval.

Indiana Michigan Power (I&M) was dismissed as a respondent.
All issues dealing with federal tax relief were addressed in the utility’s 2017/2018 rate case.

Indianapolis Power & Light (IPL)
Phase One: A settlement agreement received IURC approval.
Phase Two: All issues were addressed in the utility's 2017/2018 rate case.

Northern Indiana Public Service Company (NIPSCO)
Phase Two issues were addressed in the utility's 2018/2019 rate case.

Phase Two: Approved Settlement Agreement

Natural Gas - Large Utilities

Citizens Gas was not a respondent as it is not an investor-owned utility.

Northern Indiana Public Service Company (NIPSCO)
Phase One: Approved Tariff
Phase Two: All issues were addressed in the utility's 2018 rate case.

Vectren North
Phase Two: Approved Settlement Agreement

Vectren South
Phase Two: Approved Settlement Agreement

Natural Gas - Small Utilities

Boonville Natural Gas

Citizens Gas of Westfield was dismissed from the case.

Community Natural Gas

Fountaintown Gas

Indiana Natural Gas

Indiana Utilities Corp.

Midwest Natural Gas

Ohio Valley Gas
Phase Two: Approved Settlement Agreement

South Eastern Indiana Natural Gas

Switzerland County Natural Gas: The utility's proposed revised tariff was denied.

Sycamore Natural Gas
Phase Two: Settlement Agreement

Water/Wastewater - Large Utilities

Aqua Indiana
Approved Settlement Agreement

Citizens Water/Wastewater was not a respondent as it is not an investor-owned utility.

Indiana American Water Co.
Phase One: Approved Tariff | OUCC Testimony (Stull and Kaufman) | Subdocket Order
Phase Two: Settlement Agreement | OUCC Settlement Testimony |  Case File

Water/Wastewater -Small Utilities

American Suburban Utilities
Phase One: Approved Tariff
Phase Two: IURC Order | OUCC Testimony | Case File

The Citizens Energy Group utilities serving Westfield were dismissed from the case.

Community Utilities of Indiana
Phase One: Issues were considered through post-order filings in the utility's 2017/2018 rate case.
Phase Two: Settlement Agreement

Hamilton Southeastern Utilities

LMH Utilities

Other Small Water/Wastewater Utilities

The OUCC did not object to proposed tariffs from Devon Woods Sewer Utility and Howard County Utilities.
The OUCC did not object to dismissal requests from the following: Apple Valley Utilities, Bluffs Basin Utility, Doe Creek Sewer Utility, JLB Development, Kingsbury Utilities, Pioneer Water, Pleasantview Utilities, Wastewater One, and Webster Development.

All publicly filed documents in both phases of the investigation are available from the IURC's website.