Exhibit 10.1

QUESTAR CORPORATION

LONG-TERM STOCK INCENTIVE PLAN

AMENDMENT TO

STOCK OPTION AGREEMENTS

WITH KEITH O. RATTIE

THIS AMENDMENT TO STOCK OPTION AGREEMENTS WITH KEITH O. RATTIE, is made as of
June 28, 2010, by and between Questar Corporation, a Utah corporation (the
“Company”), and Mr. Keith O. Rattie (“Optionee”).

WHEREAS, the Company and Optionee have previously entered into the following
stock option agreements pursuant to which Optionee was granted certain stock
options (collectively, the “Options”) to purchase shares of common stock, no par
value, of the Company under the Questar Corporation Long-Term Stock Incentive
Plan (the “Plan”) (collectively, the “Option Agreements”):

Date of Stock
Option Agreement

Number of Shares
Subject to Stock Option

February 1, 2001

200,000*

February 13, 2001

200,000*

February 11, 2002

200,000*

February 11, 2003

300,000*

October 24, 2005

200,000*

February 13, 2007

80,000*

February 12, 2008

30,000

February 10, 2009

150,000

February 9, 2010

125,000

*

Amounts have been adjusted to reflect the two-for-one stock split of the
Company’s common stock that occurred on June 18, 2007.

WHEREAS, pursuant to that certain Separation Agreement, dated as of June 14,
2010, between the Company and Optionee (the “Separation Agreement”), any
unvested stock options granted to Optionee under the Plan and held by Optionee
immediately prior to the “Distribution” shall vest on the “Termination Date”
(each as defined in the Separation Agreement); and

WHEREAS, the Company and Optionee desire to amend each of the Option Agreements
as set forth herein.

NOW THEREFORE, for good and valuable consideration, the receipt and adequacy of
which are hereby acknowledged, the parties hereto hereby amend each of the
Option Agreements, other than the Option Agreement dated February 11, 2003, as
follows:

1.

The exercisability provision of each of the Option Agreements, other than the
Option Agreement dated February 11, 2003, shall be subject to the following:

“Notwithstanding any provision in this Agreement to the contrary, Optionee may
exercise all or any portion of this Option, to the extent vested, including any
portion of this Option that may become vested pursuant to the terms and
conditions of that certain Separation Agreement, dated as of June 14, 2010,
between the Company and Optionee, at any time prior to the Expiration Date,
without regard to any provision of this Agreement which provides for earlier
expiration of the Option based upon Optionee’s termination of employment with
the Company, but only with respect to the portion of this Option that either is
designated as a nonqualified stock option or has failed or fails to qualify as
an ‘incentive stock option’ as a result of the limitation set forth under
Section 422(d) of the Code.”

2.

This Amendment shall be and is hereby incorporated in and forms a part of each
of the Option Agreements, other than the Option Agreement dated February 11,
2003.

3.  

Except as expressly provided herein, all terms and conditions of each of the
Option Agreements, other than the Option Agreement dated February 11, 2003,
shall remain in full force and effect.

WHEREAS, the Option granted to Optionee under the Option Agreement dated
February 11, 2003 is fully vested as of the date hereof,

NOW THEREFORE, for good and valuable consideration, the receipt and adequacy of
which are hereby acknowledged, the parties hereto hereby amend the Option
Agreement dated February 11, 2003 as follows:

1.

The exercisability provision of the Option Agreement dated February 11, 2003
shall be subject to the following:

“Notwithstanding any provision in this Agreement to the contrary, Optionee may
exercise all or any portion of this Option, at any time prior to the Expiration
Date, without regard to any provision of this Agreement which provides for
earlier expiration of the Option based upon Optionee’s termination of employment
with the Company.”

2.

This Amendment shall be and is hereby incorporated in and forms a part of the
Option Agreement dated February 11, 2003.

3.

Except as expressly provided herein, all terms and conditions of the Option
Agreement dated February 11, 2003 shall remain in full force and effect.

[Signature Page Follows]

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IN WITNESS WHEREOF, the Company and Optionee have executed this Amendment as of
the date first above written.

OPTIONEE

QUESTAR CORPORATION

by

Keith O. Rattie

Richard Doleshek

Executive Vice President and

Chief Financial Officer

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