STOCK OPTION AWARD AGREEMENT

Exhibit 10.4

STOCK OPTION AWARD AGREEMENT

(Non-Qualified Stock Option)

This AGREEMENT is made to be effective as of March 20, 2006, by and between NB&T Financial Group, Inc. (the “COMPANY”), and John J. Limbert (the “OPTIONEE”).

WITNESSETH :

WHEREAS, the Board of Directors of the COMPANY has determined to retain the services of the OPTIONEE as the President and Chief Executive Officer of the COMPANY and its subsidiary, The National Bank and Trust Company (the “BANK”);

WHEREAS, as a material inducement to the OPTIONEE’s entering into employment with the COMPANY and the BANK and to more closely align the OPTIONEE’s interests with those of the shareholders of the COMPANY, the COMPANY wishes to award an option to purchase shares of the COMPANY to the OPTIONEE; and

WHEREAS, the Board of Directors of the COMPANY has determined to award to the OPTIONEE an option to purchase 30,000 common shares of the COMPANY, no par value per share, of the COMPANY (the “COMMON SHARES”);

NOW, THEREFORE, in consideration of the above premises and intending to be legally bound by this AGREEMENT, the parties hereto agree to the following:

1. Grant of Option . The COMPANY hereby grants to the OPTIONEE an option to purchase 30,000 COMMON SHARES (the “OPTION”). The OPTION is not intended to qualify as an incentive stock option under Section 422 of the Internal Revenue Code of 1986, as amended (the “CODE”). The COMMON SHARES to be issued upon the exercise of the OPTION may be either authorized and unissued shares or issued shares that have been reacquired by the COMPANY. No fractional shares shall be issued pursuant to this AGREEMENT.

2. Terms and Conditions of the OPTION .

(A) OPTION Price . The purchase price (the “OPTION PRICE”) to be paid by the OPTIONEE to the COMPANY upon the exercise of the OPTION shall be $20.88 per share, being 100% of the fair market value of a COMMON SHARE on March 20, 2006, as determined by the mean between the bid and the asked price of a COMMON SHARE on the NASDAQ Capital Market at the close of trading on this date.

(B) Exercise of the OPTION . Subject to the other provisions of this AGREEMENT, the OPTION is exercisable in accordance with the following schedule:

20

The OPTION shall remain exercisable until the date of expiration of the OPTION term. In the event that the employment of the OPTIONEE terminates for any reason except death, then within 90 days next succeeding such termination, but not later than 10 years from the date of grant of the option, the OPTIONEE may exercise such option rights as he then has under this AGREEMENT. To the extent the OPTION awarded pursuant to this AGREEMENT has not been exercised during such 90 days, the OPTION shall thereupon expire and shall not be exercisable thereafter. In the event of the OPTIONEE’s death, the executor or administrator of his estate may exercise the OPTIONEE’s rights under this AGREEMENT at any time within 180 days next succeeding the OPTIONEE’s death, but not later than 10 years from the effective date of this AGREEMENT. To the extent the OPTION has not been exercised within the period set forth in the preceding sentence, the OPTION shall thereupon expire and shall not be exercisable thereafter.

The OPTION may be exercised to purchase less than the total number of COMMON SHARES subject to the OPTION and exercisable at any time and from time to time. The OPTION may not be exercised unless the COMMON SHARES issued upon such exercise are first registered pursuant to any applicable federal and state laws or regulations or, in the opinion of securities counsel to the COMPANY, are exempt from such registration. Nothing contained in this AGREEMENT shall be construed to require the COMPANY to take any action whatsoever to make the OPTION exercisable or to make transferable any shares issued upon the exercise of the OPTION.

(C) Change of Control . Subject to and except as otherwise provided in this AGREEMENT, upon the occurrence of a “CHANGE OF CONTROL,” the OPTION shall become fully exercisable. A “CHANGE OF CONTROL” shall mean any one of the following events occurring after the date of this AGREEMENT: (i) the acquisition, directly or indirectly, of ownership or power to vote more than 50% of the voting stock of either of the COMPANY or the BANK; (ii) the merger of either of the COMPANY or the BANK into, or the consolidation of either of the COMPANY or the BANK with, another corporation, or the merger of another corporation into either of the COMPANY or the BANK, on a basis whereby less than fifty percent of the total voting power of the surviving corporation is represented by shares held by former shareholders of the COMPANY prior to such merger or consolidation; (iii) the acquisition of the ability to control the election of a majority of the directors of either of the COMPANY or the BANK; (iv) during any period of two consecutive years, individuals who at the beginning of such period constitute the Board of Directors of the COMPANY or the BANK cease for any reason to constitute at least a majority thereof; provided, however, that any individual whose election or nomination for election as a member of the Board of Directors of the COMPANY or the BANK was approved by a vote of at least two-thirds of the directors then in office shall be considered to have continued to be a member of the Board of Directors of the COMPANY or the BANK; (v) the acquisition by any person or entity of the power to direct the BANK’s management or policies, if the Board of Directors has made a determination that such acquisition constitutes or will constitute an acquisition of control of either of the COMPANY or the BANK for the purpose of the Bank Holding Company Act or the Change in Bank Control Act and the regulations thereunder; or (vi) the BANK shall have sold substantially all of its assets. For purposes of this paragraph, the term “person” refers to an individual or corporation, partnership, trust, association, joint venture, pool, syndicate or other organization or entity.

(D) OPTION Term . Subject to the right of the COMPANY to provide for earli