20251105Decision Memo.pdf

DECISION MEMORANDUM
TO: COMMISSIONER LODGE
COMMISSIONER HAMMOND
COMMISSIONER HARDIE
COMMISSION SECRETARY
LEGAL
WORKING FILE
FROM: JOSEPH TERRY,AUDITOR 3
JEFFREY LOLL,DEPUTY ATTORNEY GENERAL
DATE: NOVEMBER 5, 2025
RE: ANNUAL DETERMINATION OF THE INTEREST RATES ON DEPOSITS
COLLECTED FROM CUSTOMERS FOR THE CALENDAR YEAR 2026;
CASE NO. GNR-U-25-01.
Every year,the Commission establishes the interest rate to be paid by regulated utilities on
customer deposits for the next calendar year. Rule 106.02 of the Customer Relations Rules for
Gas, Electric and Water Utilities provides: "the Commission will determine the twelve-month
average interest rate for one-year Treasury Bills for the previous November 1 through October 31,
round that rate to the nearest whole percent...". IDAPA 31.21.01.106 and IDAPA 31.41.01.104.
The average interest rate for one-year Treasury Bills for November 1, 2024, through October 31,
2025, is 4.03%, as shown on Attachment A.
STAFF RECOMMENDATION
In accordance with the requirements of the Customer Relations Rules mentioned above,
Staff recommends the customer deposit rate be rounded to the nearest whole percent and set at 4%
for the calendar year 2026.
COMMISSION DECISION
Does the Commission wish to set the interest rate paid on customer deposits at 4% for the
calendar year 2026?
Jos ph Terry
Commission Staff
IAUti1ity\UDMEM0S\GNR-U-25-01 Decision Memo.docx

ATTACHMENT A
ONE-YEAR TREASURY RATES
Week Ended Rate% Week Ended Rate
11/1/2024 4.28 5/2/2025 4.00
11/8/2024 4.32 5/9/2025 4.05
11/15/2024 4.34 5/16/2025 4.13
11/22/2024 4.42 5/23/2025 4.15
11/29/2024 4.30 5/30/2025 4.11
12/6/2024 4.19 6/6/2025 4.14
12/13/2024 4.24 6/13/2025 4.09
12/20/2024 4.27 6/20/2025 4.07
12/27/2024 4.20 6/27/2025 3.97
1/3/2025 4.18 7/3/2025 4.07
1/10/2025 4.25 7/11/2025 4.09
1/17/2025 4.21 7/18/2025 4.08
1/24/2025 4.17 7/25/2025 4.09
1/31/2025 4.17 8/1/2025 3.87
2/7/2025 4.25 8/8/2025 3.93
2/14/2025 4.23 8/15/2025 3.93
2/21/2025 4.15 8/22/2025 3.87
2/28/2025 4.08 8/29/2025 3.83
3/7/2025 4.05 9/5/2025 3.65
3/14/2025 4.09 9/12/2025 3.66
3/21/2025 4.04 9/19/2025 3.60
3/28/2025 4.04 9/26/2025 3.67
4/4/2025 3.86 10/3/2025 3.64
4/11/2025 4.04 10/10/2025 3.60
4/17/2025 3.99 10/17/2025 3.56
4/25/2025 3.95 10/24/2025 3.58
10/31/2025 3.70
AVERAGE 4.03
Source: Federal Reserve Treasury Rates
One-Year Constant Maturities
https://home.treasury.gov/resource-center/data-chart-center/interest-
rates/TextView?type=daily treasury yield curve&field tdr date value=2025
ATTACHMENT A