Exhibit 99 (a)(1)(iii)

Notice of Guaranteed Delivery

For Tender of Common Stock of

HENNESSY ADVISORS, INC.

THE OFFER, PRORATION PERIOD AND WITHDRAWAL RIGHTS WILL EXPIRE AT 5:00 P.M., NEW YORK CITY TIME, ON SEPTEMBER 18, 2015, UNLESS THE OFFER IS EXTENDED OR WITHDRAWN (SUCH DATE, AS IT MAY BE EXTENDED, THE “EXPIRATION DATE”).

This Notice of Guaranteed Delivery, or a form substantially equivalent hereto, must be used to accept the Offer (as defined below) if you want to tender your Shares but:

| • |  | your certificates for the Shares (as defined below) are not immediately available or cannot be delivered to the Depositary by the Expiration Date;

| • |  | you cannot comply with the procedure for book-entry transfer by the Expiration Date; or

| • |  | your other required documents cannot be delivered to the Depositary by the Expiration Date,

in which case, you may still tender your Shares if you comply with the guaranteed delivery procedure described in Section 3 of the Offer to Purchase.

This Notice of Guaranteed Delivery, properly completed and duly executed, may be delivered to Computershare, Inc. and its wholly owned subsidiary, Computershare Trust Company, N.A. (the “Depositary”) by mail, overnight courier or by facsimile transmission (for Eligible Institutions (as defined in the Offer to Purchase) only) prior to the Expiration Date. See Section 3 of the Offer to Purchase dated August 20, 2015 (the “Offer to Purchase”).

Deliver to:

Computershare Trust Company, N.A.
Computershare Inc.

By First Class, Registered or Certified Mail: |  | By Express or Overnight Delivery:
Computershare Trust Company, N.A. |  | Computershare Trust Company, N.A.
Computershare Inc. |  | Computershare Inc.
P.O. Box 43011 |  | 250 Royall Street, Suite V
Providence, RI 02940-3011 |  | Canton, MA 02021

Fax line for Eligible Institutions only: 617-360-6810

To confirm fax for Eligible Institutions only: 781-575-2332

For this notice to be validly delivered, it must be received by the Depositary at one of the addresses listed above before the Expiration Date. Delivery of this instrument to an address other than as set forth above will not constitute a valid delivery. Deliveries to Hennessy Advisors, Inc. or Georgeson Inc. (the “Information Agent”) will not be forwarded to the Depositary and therefore will not constitute valid delivery. Deliveries to The Depository Trust Company will not constitute valid delivery to the Depositary.

This Notice of Guaranteed Delivery is not to be used to guarantee signatures. If a signature on the Letter of Transmittal is required to be guaranteed by an Eligible Institution under the instructions to the Letter of Transmittal, the signature guarantee must appear in the applicable space provided in the signature box on the Letter of Transmittal.

Ladies and Gentlemen:

The undersigned hereby tenders to Hennessy Advisors, Inc., a California corporation (“Hennessy” or the “Company”), upon the terms and subject to the conditions set forth in its Offer to Purchase, dated August 20, 2015, and the related Letter of Transmittal (which, together with any amendments or supplements thereto, collectively constitute the “Offer”), receipt of which is hereby acknowledged, the number of shares of Common Stock, no par value per share (the “Shares”), of Hennessy, listed below, pursuant to the guaranteed delivery procedures set forth in Section 3 of the Offer to Purchase.

Number of Shares to be tendered: Shares

NOTE: SIGNATURES MUST BE PROVIDED WHERE INDICATED BELOW

ODD LOTS

(See Instruction 14 to the Letter of Transmittal)

To be completed ONLY if Shares are being tendered by or on behalf of a person owning, beneficially or of record, as of the close of business on the date set forth on the signature page hereto, and who continues to own, beneficially or of record, as of the Expiration Date, an aggregate of fewer than 100 Shares.

The undersigned either (check one box):

| ¨ | is the beneficial or record owner of an aggregate of fewer than 100 Shares, all of which are being tendered; or

| ¨ | is a broker, dealer, commercial bank, trust company, or other nominee that (a) is tendering for the beneficial owner(s), Shares with respect to which it is the record holder, and (b) believes, based upon representations made to it by the beneficial owner(s), that each such person is the beneficial owner of an aggregate of fewer than 100 Shares and is tendering all of the Shares beneficially owned by each such person.

CONDITIONAL TENDER

(See Instruction 13 to the Letter of Transmittal)

A shareholder may tender Shares subject to the condition that a specified minimum number of the shareholder’s Shares tendered pursuant to the Letter of Transmittal must be purchased if any Shares tendered are purchased, all as described in the Offer to Purchase, particularly in Section 6 thereof. Unless at least the minimum number of Shares indicated below is purchased by Hennessy pursuant to the terms of the Offer, none of the Shares tendered will be purchased. It is the tendering shareholder’s responsibility to calculate that minimum number of Shares that must be purchased if any are purchased, and Hennessy urges shareholders to read carefully Section 13 of the Offer to Purchase and consult their own tax advisors before completing this section. Unless this box has been checked and a minimum specified, the tender will be deemed unconditional.

| ¨ | The minimum number of Shares that must be purchased, if any are purchased, is: Shares.

If, because of proration, the minimum number of Shares designated will not be purchased, Hennessy may accept conditional tenders by random lot, if necessary. However, to be eligible for purchase by random lot, the tendering shareholder must have tendered all of his or her Shares and checked this box:

| ¨ | The tendered Shares represent all Shares held by the undersigned.

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CERTIFICATION BY NON-U.S. HOLDERS

TENDERING ALL SHARES ACTUALLY AND CONSTRUCTIVELY OWNED (To be completed only

By a Non-U.S. Holder who is tendering all of his, her or its Shares, or by a nominee acting on behalf of a Non-U.S. Holder who is tendering all of his, her or its Shares. See Instruction 10 of the Letter of Transmittal)

The undersigned represents that either (check one box):

¨ the undersigned is the beneficial owner of Shares and is tendering all of the undersigned’s Shares, including those owned directly and constructively (see Section 13 of the Offer to Purchase); or

¨ the undersigned is a broker, dealer, commercial bank, trust company or other nominee which: (a) is tendering, for the beneficial owner(s) thereof, Shares with respect to which the undersigned is the record owner; and (b) believes, based upon representations made to the undersigned by such beneficial owners, that each such person is tendering all of their Shares, including those owned directly and constructively (see Section 13 of the Offer to Purchase).

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PLEASE SIGN ON THIS PAGE

(Also Please Complete IRS Form W-9 or Appropriate IRS Form W-8)

Name(s) of Record Holder(s):
(Please Print)
Signature(s):
X: |  |
X: |  |

Address(es): |  |  |
Zip code(s): |  |  |

(Area code) and telephone number : |  |

If delivery will be by book-entry transfer, check this box: ¨ |

Name of tendering institution: |  |  |

Account number: |  |  |

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GUARANTEE
(NOT TO BE USED FOR SIGNATURE GUARANTEE)

The undersigned, a bank, broker, dealer, credit union, savings association or other entity which is a member in good standing of the Securities Transfer Association Medallion Signature Guarantee Program, or an “eligible guarantor institution,” (as such term is defined in Rule 17Ad-15 under the Securities Exchange Act of 1934, as amended (the “Exchange Act”)), hereby guarantees (i) that the above-named person(s) has a net long position in the Shares being tendered within the meaning of Rule 14e-4 under the Exchange Act, (ii) that such tender of Shares complies with Rule 14e-4 under the Exchange Act and (iii) to deliver to the Depositary at an applicable address set forth above certificate(s) for the Shares tendered hereby, in proper form for transfer, or a confirmation of the book-entry transfer of the Shares into the Depositary’s account at The Depository Trust Company, together with a properly completed and duly executed Letter of Transmittal (or a manually signed facsimile thereof) and any other required documents, within three business days after the date of receipt by the Depositary.

|  | X |  |
Name of Eligible Institution Guaranteeing Delivery |  |  |  | Authorized Signature
Address |  |  |  | Name (Print Name)
Zip Code |  |  |  | Title
(Area Code) Telephone No. |  |  |  | Dated:_______________________, 2015

This form is not to be used to guarantee signatures. If a signature on a Letter of Transmittal is required to be guaranteed by an Eligible Institution under the Instructions thereto, such signature guarantee must appear in the applicable space provided in the signature box on the Letter of Transmittal.

NOTE: DO NOT SEND SHARE CERTIFICATES WITH THIS FORM. YOUR SHARE CERTIFICATES MUST BE SENT WITH THE LETTER OF TRANSMITTAL.

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