Otter Tail (OTTR) director Nathan Partain awarded 2,000 restricted shares

Rhea-AI Filing Summary

PARTAIN NATHAN I reported acquisition or exercise transactions in this Form 4 filing.

Otter Tail Corp director Nathan I. Partain reported receiving a grant of 2,000 shares of Common Stock on April 13, 2026, classified as a grant or award rather than an open-market purchase. The shares are Restricted Stock issued under the 2023 Stock Incentive Plan and carry a stated fair market value of $91.15.

The Restricted Stock will vest in near-equal installments of one-third per year beginning April 8, 2027. After this award, Partain holds 10,969 shares directly, plus indirect holdings of 1,600 shares through an IRA and 67,561 shares through a trust.

Insights

Equity compensation analyst

Director receives routine restricted stock grant as part of equity compensation.

Otter Tail Corp granted director Nathan I. Partain 2,000 Restricted Stock shares under the 2023 Stock Incentive Plan. This is a compensation award, not an open-market purchase, and therefore carries weaker signaling value for investor sentiment than discretionary buying.

The award vests in one-third increments starting on April 8, 2027, creating a multi-year retention incentive. Following the grant, Partain’s position includes 10,969 direct shares and significant indirect holdings via an IRA and a trust, indicating continued exposure to the company’s equity.

Insider Trade Summary

3 transactions reported

Mixed 3 txns

Insider PARTAIN NATHAN I

Role Director

Type	Security	Shares	Price	Value
Grant/Award	Common Stock	2,000	$0.00	--
holding	Common Stock	--	--	--
holding	Common Stock	--	--	--

Holdings After Transaction: Common Stock — 10,969 shares (Direct); Common Stock — 1,600 shares (Indirect, By IRA)

Footnotes (1)

1. Shares of Common Stock acquired under the 2023 Stock Incentive Plan, which is a grant of Restricted Stock. The shares granted on April 13, 2026 will vest in near-equal installments of one-third per year beginning April 8, 2027. This grant has a fair market value of $91.15. Total direct holdings include shares acquired individually through the Dividend Reinvestment Plan and shares acquired individually pursuant to Restricted Stock Award distributions.

Key Figures

Restricted Stock grant: 2,000 shares Direct holdings after grant: 10,969 shares Indirect IRA holdings: 1,600 shares +2 more

5 metrics

Restricted Stock grant 2,000 shares Grant of Common Stock on April 13, 2026

Direct holdings after grant 10,969 shares Total direct Common Stock ownership following transaction

Indirect IRA holdings 1,600 shares Common Stock held indirectly by IRA after transaction

Indirect trust holdings 67,561 shares Common Stock held indirectly by trust after transaction

Grant fair market value $91.15 Fair market value stated for this Restricted Stock grant

Key Terms

Restricted Stock, 2023 Stock Incentive Plan, Dividend Reinvestment Plan, IRA, +1 more

5 terms

Restricted Stock financial

"which is a grant of Restricted Stock. The shares granted on April 13, 2026"

Shares granted to an individual that carry limits on transfer or sale until certain conditions are met, such as staying with the company for a set time or hitting performance targets. Think of them as a locked gift that gradually opens; for investors they matter because they affect how many shares may enter the market later, signal management incentives and potential dilution, and reveal confidence in future company performance.

2023 Stock Incentive Plan financial

"Shares of Common Stock acquired under the 2023 Stock Incentive Plan, which is a grant"

Dividend Reinvestment Plan financial

"include shares acquired individually through the Dividend Reinvestment Plan and shares acquired"

A dividend reinvestment plan lets shareholders automatically use cash dividends to buy more shares of the same company instead of receiving the money. It matters to investors because it turns regular payouts into a steady way to grow ownership and take advantage of compound returns—like having your savings automatically buy additional slices of a pie over time—while often reducing transaction costs and smoothing purchase timing.

IRA financial

"total_shares_following_transaction": "1600.0000", "direct_or_indirect": "I", "nature_of_ownership": "By IRA""

An individual retirement account (IRA) is a savings account designed to help people put aside money for their retirement, often with tax advantages that encourage long-term savings. It matters to investors because it can grow over time, providing financial security later in life, and offers benefits that can reduce current taxes or allow investments to compound more effectively.

trust financial

"total_shares_following_transaction": "67561.0000", "direct_or_indirect": "I", "nature_of_ownership": "by Trust""

Form 4 Insider Transactions: What Each Field Means →

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

PARTAIN NATHAN I

(Last) (First) (Middle)

215 SOUTH CASCADE STREET

(Street)

FERGUS FALLS MINNESOTA 56537

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Otter Tail Corp [ OTTR ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
04/13/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	04/13/2026		A(1)		2,000	A	(2)	10,969(3)	D
Common Stock								1,600	I	By IRA
Common Stock								67,561	I	by Trust

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Shares of Common Stock acquired under the 2023 Stock Incentive Plan, which is a grant of Restricted Stock. The shares granted on April 13, 2026 will vest in near-equal installments of one-third per year beginning April 8, 2027.

2. This grant has a fair market value of $91.15.

3. Total direct holdings include shares acquired individually through the Dividend Reinvestment Plan and shares acquired individually pursuant to Restricted Stock Award distributions.

Remarks:

	/s/ Nathan I. Partain by James A. Versteeg, Attorney-in-Fact	04/14/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

FAQ

What did Otter Tail Corp (OTTR) director Nathan Partain receive in this Form 4 filing?

Director Nathan I. Partain received a grant of 2,000 shares of Otter Tail Corp Common Stock as Restricted Stock on April 13, 2026, issued under the company’s 2023 Stock Incentive Plan as part of his equity-based compensation.

Is Nathan Partain’s 2,000-share Otter Tail (OTTR) award an open-market stock purchase?

No. The 2,000-share transaction is reported with code A as a grant or award of Restricted Stock under a stock incentive plan, not an open-market purchase, so it reflects compensation rather than a discretionary buy in the market.

How and when will Nathan Partain’s Otter Tail (OTTR) Restricted Stock grant vest?

The 2,000 Restricted Stock shares will vest in near-equal installments of one-third per year, beginning on April 8, 2027. This schedule phases in ownership over three years, encouraging longer-term alignment with shareholder interests.

What are Nathan Partain’s total direct and indirect Otter Tail (OTTR) share holdings after the grant?

After the grant, Nathan Partain holds 10,969 shares directly, plus 1,600 shares indirectly by IRA and 67,561 shares indirectly by trust. These figures reflect both his personal and related-entity ownership positions reported in the filing.

How was the fair market value of Nathan Partain’s Otter Tail (OTTR) Restricted Stock grant described?

A footnote states that this grant has a fair market value of $91.15. The filing does not elaborate further on the calculation method, but this figure is disclosed in connection with the 2,000-share Restricted Stock award under the 2023 Stock Incentive Plan.

What does the Form 4 say about how Nathan Partain accumulated his direct Otter Tail (OTTR) holdings?

A footnote notes that total direct holdings include shares acquired individually through the Dividend Reinvestment Plan and shares received from Restricted Stock Award distributions, indicating a combination of plan participation and prior equity awards.