UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d) OF

THE SECURITIES EXCHANGE ACT OF 1934

DATE OF REPORT (DATE OF EARLIEST EVENT REPORTED): January 15, 2013

AUTHENTIDATE HOLDING CORP.

(Exact name of registrant as specified in its charter)

COMMISSION FILE NUMBER: 0-20190

Connell Corporate Center

300 Connell Drive, 5^th Floor

Berkeley Heights, New Jersey 07922

(Address and zip code of principal executive offices)

(908) 787-1700

(Registrant’s telephone number, including area code

CHECK THE APPROPRIATE BOX BELOW IF THE FORM 8-K FILING IS INTENDED TO SIMULTANEOUSLY SATISFY THE FILING OBLIGATION OF THE REGISTRANT UNDER ANY OF THE FOLLOWING PROVISIONS:

To the extent required to be disclosed pursuant to this Item 1.01, the information set forth in Item 5.02 of this Current Report on Form 8-K is incorporated herein by reference.

(e) On January 15, 2013, Authentidate Holding Corp. (the “company”) entered into agreements with each of its chief executive officer, O’Connell Benjamin, and chief financial officer, William A. Marshall, in order to continue and expand the compensation modification program originally implemented in February 2010. Pursuant to these agreements, both officers agreed to accept a further reduction in their base salary to 70% of their original base salary. The reduction in base salary commenced January 16, 2013 and continues until the first to occur of the company achieving “cash flow breakeven” or January 15, 2014.

Pursuant to these new modification agreements, the term “cash flow breakeven” was modified from the definition adopted when the company originally implemented this program and is now defined to mean that the company has achieved positive cash flow from operations for two consecutive fiscal quarters, determined by reference to the revenues and other amounts received by the company from its operations. The term “cash flow from operations”, however, shall not include (a) amounts received from the sale, lease or disposition of (i) fixed or capital assets, except for amounts received in the ordinary course of business; or (ii) any subsidiary company; (b) capital expenditures; (c) interest income and expense; and (d) other non-operating items as determined in accordance with generally accepted accounting principles in the United States as consistently applied during the periods involved.

In consideration for entering into these agreements, the company granted both executive officers such number of restricted stock units (“RSUs”) as is equal to the total amount of base salary that each agreed to forego pursuant to the new compensation modification agreement for the twelve month period expiring January 15, 2014 divided by the fair value of the company’s common stock, which is based on the closing price of the company’s common stock, on the grant date. Each RSU represents the contingent right to receive, upon vesting, one share of the company’s common stock. Accordingly, we granted our chief executive officer 62,431RSUs and granted our chief financial officer 55,972 RSUs. The RSUs were granted under the company’s 2011 Omnibus Equity Incentive Plan (the “2011 Plan”), and except as otherwise provided for in the RSU agreement and compensation modification agreements, the RSUs shall vest upon the date determined that the company achieves cash flow breakeven, as defined above.

Further, in connection with the continuation of the company’s compensation modification program, all other employees that are subject to salary modifications were granted RSUs under the company’s 2011 Plan in consideration for the continued salary reduction. The salaries of non-executive employees earning $110,000 per annum or less will continue to be reduced by 10% until January 15, 2014 and the salaries of the company’s other non-executive employees will be reduced by an additional 15% for a total reduction of 30% of their original base salary for the twelve month period ending January 15, 2014. In consideration for these reductions, the company awarded these employees RSUs based on the same calculation as applicable to our executive officers. Accordingly, we will grant our non-executive employees a total of up to 462,515 RSUs. The RSUs awarded to the non-executive employees are subject to the same terms and conditions as applicable to our executive officers as described above, except to the extent that the awards granted to our executives provide for accelerated vesting in certain circumstances, as required by their employment agreements with the company.

In addition, in connection with the foregoing, we also amended the vesting provision of “cash flow breakeven performance” applicable to the options granted to our employees (including executive officers) in February 2010, February 2011 and June 2012 (collectively, the “Modification Options”) under the compensation modification program. The changes to the Modification Options are to amend the definition of “cash flow breakeven performance” as used therein to delete the requirement of a specific measurement period for determining whether the company achieves this vesting condition. Accordingly, the Modification Options will not be forfeited in the event the company does not achieve cash flow breakeven performance by September 30, 2013 and will vest as long as the company achieves cash flow breakeven performance prior to the expiration date of such options (or sooner in accordance with their terms). Each Modification Option previously granted has an initial expiration date of 10 years from the grant date and the company did not extend or adjust the originally stated expiration dates of the Modification Options.

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In addition, on January 15, 2013, the company entered into agreements with each of its chief executive officer and chief financial officer to amend the company’s existing employment agreements with these officers. The purpose of the amendments was to update certain provisions of their employment agreements to address compliance with Section 409A of the Internal Revenue Code of 1986, as amended.

The foregoing summaries of the terms of the compensation modification agreements and employment agreement amendments that the company entered into with its chief executive and chief financial officers are qualified by reference to the full text of such agreements, which are filed as exhibits to this Current Report on Form 8-K and incorporated herein by reference.

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SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, hereunto duly authorized.

Date: January 17, 2013

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EXHIBIT INDEX

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