(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Approximate date of commencement of proposed sale to the public: From time to time after the effective date of this registration statement.

If the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, check the following box. ¨

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box. x

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ¨

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ¨

If this Form is a registration statement pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective upon filing with the Commission pursuant to Rule 462(e) under the Securities Act, check the following box. ¨

If this Form is a post-effective amendment to a registration statement filed pursuant to General Instruction I.D. filed to register additional securities or additional classes of securities pursuant to Rule 413(b) under the Securities Act, check the following box. ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

The registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until the registration statement shall become effective on such date as the Commission, acting pursuant to said Section 8(a), may determine.

The base prospectus immediately follows this explanatory note. The at-the-market offering prospectus immediately follows the base prospectus. The common stock that may be offered, issued and sold by the registrant under the at-the-market offering prospectus is included in the $100,000,000 of securities that may be offered, issued and sold by the registrant under the base prospectus. Upon the termination of the sales agreement with Ascendiant Capital Markets, LLC, any portion of the $25,000,000 of securities included in the at-the-market offering prospectus that is not sold pursuant to the sales agreement will be available for sale in other offerings pursuant to the base prospectus and one or more accompanying prospectus supplements.

The information in this prospectus is not complete and may be changed. We may not sell these securities until the registration statement filed with Securities and Exchange Commission is effective. This prospectus is not an offer to sell these securities, and it is not soliciting an offer to buy these securities, in any state where the offer or sale is not permitted.

We may offer and sell from time to time, in one or more offerings and on terms that we will determine at the time of each offering, shares of common stock, shares of preferred stock, debt securities and/or warrants, either separately, together with other securities covered by this prospectus or as units consisting of two or more of the securities covered by this prospectus. The debt securities, preferred stock and warrants may be convertible into or exercisable or exchangeable for common stock, preferred stock or debt securities. The aggregate offering price of all securities sold under this prospectus will not exceed $100,000,000.

We will provide the specific terms of each offering of securities, including the price and the type and amount of securities to be offered and sold, in a supplement to this prospectus. You should read this prospectus and the prospectus supplement carefully before you invest.

We may offer and sell these securities directly to purchasers or to or through one or more underwriters, dealers and agents, and on a continuous or delayed basis. If we sell securities to or through underwriters, dealers or agents, we will include their names and the fees, commissions and discounts that they will receive, as well as the net proceeds to us, in the prospectus supplement. This prospectus may not be used to sell our securities unless it is accompanied by the prospectus supplement. The delivery of this prospectus together with a prospectus supplement relating to the offered securities shall not constitute an offer of any other securities covered by this prospectus.

Investing in our securities involves a high degree of risk. See “Risk Factors” on page 3 of this prospectus and in the applicable prospectus supplement for a discussion of risks that you should consider before you invest in our securities.

Our common stock is traded on the OTCQB under the symbol “SGLB.” On December 16, 2014, the last reported sale price of our common stock on the OTCQB was $0.0745 per share.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus. Any representation to the contrary is a criminal offense.

This prospectus is a part of a registration statement on Form S-3 that we filed with the Securities and Exchange Commission (the “SEC”) utilizing a “shelf” registration process. Under the shelf registration process, we may sell any combination of the securities described in this prospectus in one or more transactions up to a total dollar amount of $100,000,000.

The rules and regulations of the SEC allow us to omit from this prospectus certain information that is included in the registration statement. For further information about us and our securities, you should review the registration statement and the exhibits filed with the registration statement. In addition, the SEC allows us to incorporate by reference into this prospectus information in the reports and other documents that we file with the SEC, which means that we can disclose important information to you by referring you to those reports and other documents. The information incorporated by reference is considered to be part of this prospectus, and information that we later file with the SEC will automatically update and, where applicable, modify or supersede that information. You may read the registration statement (including its exhibits) and the reports and other documents that we file with the SEC at the SEC’s website, www.sec.gov, or at the SEC’s Public Reference Room described below under the heading “Where You Can Find More Information.”

This prospectus provides you with a general description of the securities we may offer. Each time we offer securities under this shelf registration, we will provide a prospectus supplement that will contain specific information about the terms of that offering. The prospectus supplement may also add, update or change information contained in this prospectus. You should read both this prospectus and any prospectus supplement together with the additional information described under the heading “Incorporation of Certain Information by Reference.” To the extent that any information in the prospectus supplement is inconsistent with the information in this prospectus, the information in the prospectus supplement will modify or supersede this prospectus.

This prospectus and the related prospectus supplement do not constitute an offer to sell or the solicitation of an offer to buy any securities other than the registered securities to which they relate, nor do this prospectus and the related prospectus supplement constitute an offer to sell or the solicitation of an offer to buy securities in any jurisdiction to any person to whom it is unlawful to make such offer or solicitation in such jurisdiction.

You should not assume that the information contained in this prospectus and the related prospectus supplement is accurate as of any date subsequent to the date set forth on the front of the document or that any information we have incorporated by reference is correct as of any date subsequent to the date of the document incorporated by reference, even though this prospectus and any related prospectus supplement is delivered or securities are sold on a later date. Our business, financial condition, results of operations and prospects may have changed since those dates.

You should rely only on the information contained in this prospectus, in the related prospectus supplement and in any documents incorporated by reference into this prospectus. We have not authorized any salesperson, dealer or other person to provide you with information different from that contained in this prospectus, in the related prospectus supplement or in any documents incorporated by reference into this prospectus, and you are not entitled to rely upon any such different information.

References in this prospectus to “Sigma Labs,” “we,” “us” and “our” refer to Sigma Labs, Inc. and its subsidiaries.

We are a technology company that specializes in the development and commercialization of novel and unique manufacturing and materials technologies. We believe that some of these technologies may fundamentally redefine conventional quality assurance and control practices by embedding quality assurance and process control into the manufacturing process in real time. In addition, we anticipate that our core technologies will enable our clientele to combine advanced manufacturing quality assurance and control protocols with novel materials to achieve breakthrough product potential in many industries including aerospace, defense, oil and gas, bio-medical and power generation.

Certain members of our team are uniquely qualified scientists with broad backgrounds in manufacturing and materials technologies. In the past, these members have worked with some of the largest defense contractors in the world, in such varied projects as next-generation manufacturing systems, advanced reactive munitions, nuclear weapons stewardship programs, and naval nuclear reactor programs.

Our current business plan and principal business activities include the continued development of our In-Process Quality Assurance™ (IPQA®) suite of technologies and eventual commercialization of both our IPQA® and materials-related suite of technologies, with our main focus currently on the 3D Printing industry. Our strategy is to leverage our manufacturing and materials knowledge, experience and capabilities through the following means:

We are presently engaged in a variety of activities in which we seek to commercialize technologies and products in the following industry sectors:

We expect to generate revenues primarily by selling or licensing our manufacturing and materials technologies. We plan to assist our commercialization partners with marketing-related activities for those advanced material-related technologies, including our dental implant biomedical prosthetics technology, for which we seek possible commercialization in the future. However, we presently make no sales of these technologies and generate no revenues therefrom. Since inception, we have generated revenues primarily from engineering consulting services provided to third parties.

Our principal executive offices are located at 3900 Paseo del Sol, Santa Fe, New Mexico 87507, and our telephone number is (505) 438-2576. Our website address is www.sigmalabsinc.com, although the information on our website is not deemed to be part of this prospectus.

Investing in our securities involves a high degree of risk. Before you decide whether to purchase any of our securities, in addition to the other information in this prospectus and the related prospectus supplement, you should carefully consider the risks described under the heading “Risk Factors” in our most recent Annual Report on Form 10-K and subsequently filed Quarterly Reports on Form 10-Q, which are incorporated by reference into this prospectus, as the same may be updated from time to time by our future filings with the SEC. You should also carefully consider any additional risks that are described in the prospectus supplement related to the offering of our securities. If one or more of these risks materializes, our business, financial condition and results of operations may be adversely affected. In that event, the value of our securities could decline.

This prospectus and the documents incorporated herein by reference contain forward-looking statements, and we anticipate that the related prospectus supplement will contain forward-looking statements. These statements relate to future events or to our future financial performance and involve known and unknown risks, uncertainties and other factors that may cause our actual results to be materially different from any future results expressed or implied by the forward-looking statements. In some cases, you can identify forward-looking statements by the use of words such as “believe,” “anticipate,” “intend,” “plan,” “estimate,” “may,” “could,” “anticipate,” “predict,” or “expect” and similar expressions. You should not place undue reliance on forward-looking statements since they involve known and unknown risks, uncertainties and other factors that are, in many cases, beyond our control. Forward-looking statements are not guarantees of future performance. Actual events or results may differ materially from those discussed in the forward-looking statements as a result of various factors. Except as required by applicable law, we do not undertake any obligation to publicly update any forward-looking statements, whether as a result of new information, future developments or otherwise.

We will discuss certain of these risks and uncertainties in greater detail in any prospectus supplement under the heading “Risk Factors.” Additional cautionary statements or discussions of risks and uncertainties that could affect our results or the achievement of the expectations described in forward-looking statements may also be contained in the documents we incorporate by reference into this prospectus, including our most recent Annual Report on Form 10-K filed with the SEC and our Quarterly Reports on Form 10-Q filed subsequently with the SEC.

Unless we state otherwise in the applicable prospectus supplement, we intend to use the net proceeds from the sale of securities described in this prospectus for general corporate purposes which may include, among other things, reducing indebtedness, acquiring other businesses (although we currently have no agreement to acquire any business), repurchasing our common stock and making capital expenditures, as well as for working capital. Until we use the net proceeds for these purposes, we intend to invest the net proceeds in investment-grade, interest-bearing securities. We have not determined the amounts we plan to spend on any of these areas or the timing of these expenditures. As a result, our management will have broad discretion regarding the application of the net proceeds from the sale of securities described in this prospectus.

We, directly or through underwriters, dealers or agents designated by us from time to time, may offer, issue and sell, together or separately, up to $100,000,000 in the aggregate of:

The common stock, the preferred stock, the debt securities, the warrants and the units collectively are referred to in this prospectus as the “securities.”

We have summarized below the material terms of the various types of securities that we may offer. We will describe in the applicable prospectus supplement the detailed terms of the securities offered by that supplement. If indicated in the prospectus supplement, the terms of the offered securities may differ from the terms summarized below.

This prospectus may not be used to sell our securities unless it is accompanied by the applicable prospectus supplement.

We have authority to issue 750,000,000 shares of common stock, par value $0.001 per share. As of December 16, 2014, 619,741,061 shares of our common stock were outstanding and there were outstanding warrants to purchase 18,796,296 shares of our common stock. The following summary of our common stock is qualified by reference to the provisions of our articles of incorporation and bylaws, which are filed as exhibits to the Form S-3 registration statement of which this prospectus is a part.

We have one class of common stock. Holders of our common stock are entitled to one vote per share on all matters to be voted upon by stockholders and do not have cumulative voting rights in the election of directors. Holders of shares of common stock are entitled to receive on a pro rata basis such dividends, if any, as may be declared from time to time by our board of directors in its discretion from funds legally available for that use, subject to any preferential dividend rights of outstanding preferred stock. They are also entitled to share on a pro rata basis in any distribution to our common stockholders upon our liquidation, dissolution or winding up, subject to the prior rights of any outstanding preferred stock. Common stockholders do not have preemptive rights to subscribe to any additional stock issuances by us, and they do not have the right to require the redemption of their shares or the conversion of their shares into any other class of our stock. The rights, preferences and privileges of holders of common stock are subject to, and may be adversely affected by, the rights of the holders of any series of preferred stock that we may designate and issue in the future.

The following provisions of our articles of incorporation and bylaws could have the effect of delaying or discouraging another party from acquiring control of us and could encourage persons seeking to acquire control of us to first negotiate with our board of directors:

The transfer agent and registrar of our common stock is Interwest Transfer Company, Inc. The address of our transfer agent and registrar is 1981 Murray Holladay Road, Suite 100 Salt Lake City, Utah 84117, and its telephone number is (801) 272-9294.

We have authority to issue 10,000,000 shares of preferred stock, par value $0.001 per share. As of the date of this prospectus, no shares of our preferred stock were outstanding.

Under our articles of incorporation, our board of directors has the authority, without further action by stockholders, to designate one or more series of preferred stock and to fix the voting powers, designations, preferences, limitations, restrictions and relative rights granted to or imposed upon the preferred stock, including dividend rights, conversion rights, voting rights, rights and terms of redemption, liquidation preference and sinking fund terms, any or all of which may be preferential to or greater than the rights of the common stock.

Our board of directors may authorize the issuance of preferred stock with voting or conversion rights that could adversely affect the voting power or other rights of the holders of the common stock. The issuance of preferred stock, while providing flexibility in connection with possible acquisitions and other corporate purposes, could, among other things, have the effect of delaying, deferring or preventing a change in our control and may adversely affect the market price of the common stock and the voting and other rights of the holders of common stock.

We will describe in a prospectus supplement relating to any series of preferred stock being offered the following terms:

Unless we specify otherwise in the applicable prospectus supplement, the preferred stock will rank, relating to dividends and upon our liquidation, dissolution or winding up:

The following is a summary of the general terms of the debt securities that we may offer. We will file a prospectus supplement that may contain additional terms when we issue debt securities. The terms presented here, together with the terms in a related prospectus supplement, will be a description of the material terms of the debt securities. You should also read the indenture under which the debt securities are to be issued. We have filed a form of indenture governing different types of debt securities with the SEC as an exhibit to the registration statement of which this prospectus is a part.

We may issue, from time to time, debt securities, in one or more series. The debt securities we offer will be issued under an indenture between us and the trustee named in the indenture. The debt securities that we may issue include senior debt securities, subordinated debt securities, convertible debt securities and exchangeable debt securities.

The following is a summary of the material provisions of the indenture filed as an exhibit to the registration statement of which this prospectus is a part. For each series of debt securities, the applicable prospectus supplement for the series may change and supplement the summary below.

The indenture provides that we may issue debt securities up to the principal amount that we may authorize, and they may be in any currency or currency unit that we may designate. Except for the limitations on consolidation, merger and sale of all or substantially all of our assets contained in the indenture, the terms of the indenture do not contain any covenants or other provisions designed to give holders of any debt securities protection against changes in our operations, financial condition or transactions involving us. For each series of debt securities, any restrictive covenants for those debt securities will be described in the applicable prospectus supplement for those debt securities.

We may issue the debt securities issued under the indenture as “discount securities,” which means they may be sold at a discount below their stated principal amount. These debt securities, as well as other debt securities that are not issued at a discount, may, for United States federal income tax purposes, be treated as if they were issued with “original issue discount” because of interest payment and other characteristics. Special U.S. federal income tax considerations applicable to debt securities issued with original issue discount will be described in more detail in any applicable prospectus supplement.

You should refer to the prospectus supplement relating to a particular series of debt securities for a description of the following terms of the debt securities offered by that prospectus supplement and by this prospectus:

The applicable prospectus supplement will present material United States federal income tax considerations for holders of any debt securities and the securities exchange or quotation system on which any debt securities are to be listed or quoted.

Debt securities may be convertible into or exchangeable for shares of our equity securities or other securities. The terms and conditions of conversion or exchange will be stated in the applicable prospectus supplement. The terms will include, among others, the following:

We cannot consolidate or merge with or into, or transfer or lease all or substantially all of our assets to, any person, unless the successor corporation or person to which our assets are transferred or leased is organized under the laws of the United States, any state of the United States or the District of Columbia and it expressly assumes our obligations under the debt securities and the indenture. In addition, we cannot complete such a transaction unless immediately after completing the transaction, no event of default under the indenture, and no event that, after notice or lapse of time or both, would become an event of default under the indenture, has occurred and is continuing. When the person to whom our assets are transferred or leased has assumed our obligations under the debt securities and the indenture, we will be discharged from all our obligations under the debt securities and the indenture except in limited circumstances.

This covenant would not apply to any recapitalization transaction, a change of control affecting us or a highly leveraged transaction, unless the transaction or change of control were structured to include a merger or consolidation or transfer or lease of all or substantially all of our assets.

The indenture provides that the following will be “events of default” with respect to any series of debt securities:

An event of default for a particular series of debt securities does not necessarily constitute an event of default for any other series of debt securities issued under the indenture. For each series of debt securities, any modifications to the above events of default will be described in the applicable prospectus supplement for those debt securities.

The indenture provides that if an event of default specified in the first, second, third, fourth or sixth bullets above occurs and is continuing, either the trustee or the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series may declare the principal amount of all those debt securities (or, in the case of discount securities or indexed securities, that portion of the principal amount as may be specified in the terms of that series) to be due and payable immediately. If an event of default specified in the fifth bullet above occurs and is continuing, then the principal amount of all those debt securities (or, in the case of discount securities or indexed securities, that portion of the principal amount as may be specified in the terms of that series) will be due and payable immediately, without any declaration or other act on the part of the trustee or any holder. In certain cases, holders of a majority in principal amount of the outstanding debt securities of any series may, on behalf of holders of all those debt securities, rescind and annul a declaration of acceleration.

The indenture imposes limitations on suits brought by holders of debt securities against us. Except for actions for payment of overdue principal or interest, no holder of debt securities of any series may institute any action against us under the indenture unless:

We will be required to file annually with the trustee a certificate, signed by one of our officers, stating whether or not the officer knows of any default by us in the performance, observance or fulfillment of any condition or covenant of the indenture.

We can discharge or decrease our obligations under the indenture as stated below.

We may discharge obligations to holders of any series of debt securities that have not already been delivered to the trustee for cancellation and that have either become due and payable or are by their terms to become due and payable, or are scheduled for redemption, within one year. We may effect a discharge by irrevocably depositing with the trustee cash or government obligations denominated in the currency of the debt securities, as trust funds, in an amount certified to be enough to pay when due, whether at maturity, upon redemption or otherwise, the principal of, and any premium and interest on, the debt securities and any mandatory sinking fund payments.

Unless otherwise provided in the applicable prospectus supplement, we may also discharge any and all of our obligations to holders of any series of debt securities at any time, which we refer to as defeasance. We may also be released from the obligations imposed by any covenants of any outstanding series of debt securities and provisions of the indenture, and we may omit to comply with those covenants without creating an event of default under the trust declaration, which we refer to as covenant defeasance. We may effect defeasance and covenant defeasance only if, among other things:

In the case of a defeasance by us, the opinion we deliver must be based on a ruling of the Internal Revenue Service issued, or a change in U.S. federal income tax law occurring, after the date of the indenture, since such a result would not occur under the U.S. federal income tax laws in effect on that date.

Although we may discharge or decrease our obligations under the indenture as described in the preceding paragraphs, we may not avoid, among other things, our duty to register the transfer or exchange of any series of debt securities, to replace any temporary, mutilated, destroyed, lost or stolen series of debt securities or to maintain an office or agency in respect of any series of debt securities.

The indenture provides that we and the trustee may enter into supplemental indentures without the consent of the holders of debt securities to, among other things:

The indenture also provides that we and the trustee may, with the consent of the holders of not less than a majority in aggregate principal amount of debt securities of each series of debt securities affected by such supplemental indenture then outstanding, add any provisions to, or change in any manner, eliminate or modify in any way the provisions of, the indenture or any supplemental indenture or modify in any manner the rights of the holders of the debt securities. We and the trustee may not, however, without the consent of the holder of each outstanding debt security affected thereby:

The indenture provides that the holders of not less than a majority in aggregate principal amount of the then-outstanding debt securities of any series, by notice to the relevant trustee, may on behalf of the holders of the debt securities of that series waive any default and its consequences under the indenture except:

The debt securities of a series may be issued in whole or in part in book-entry form and will be represented by one or more fully registered global securities. We will deposit any registered global securities with a depositary or with a nominee for a depositary identified in the applicable prospectus supplement and registered in the name of such depositary or nominee. In such case, we will issue one or more registered global securities denominated in an amount equal to the aggregate principal amount of all of the debt securities of the series to be issued and represented by such registered global security or securities. This means that we will not issue certificates to each holder.

Unless and until it is exchanged in whole or in part for debt securities in definitive registered form, a registered global security may not be transferred except as a whole:

The prospectus supplement relating to a series of debt securities will describe the specific terms of the depositary arrangement involving any portion of the series represented by a registered global security. We anticipate that the following provisions will apply to all depositary arrangements for debt securities:

The laws of some states may require that specified purchasers of securities take physical delivery of the securities in definitive form. These laws may limit the ability of those persons to own, transfer or pledge beneficial interests in registered global securities.

So long as the depositary for a registered global security, or its nominee, is the registered owner of the registered global security, the depositary or such nominee, as the case may be, will be considered the sole owner or holder of the debt securities represented by the registered global security for all purposes under the indenture. Except as stated below, owners of beneficial interests in a registered global security:

Accordingly, each person owning a beneficial interest in a registered global security must rely on the procedures of the depositary for the registered global security and, if the person is not a participant, on the procedures of a participant through which the person owns its interest, to exercise any rights of a holder under the indenture.

We understand that under existing industry practices, if we request any action of holders or if an owner of a beneficial interest in a registered global security desires to give or take any action that a holder is entitled to give or take under the indenture, the depositary for the registered global security would authorize the participants holding the relevant beneficial interests to give or take the action, and the participants would authorize beneficial owners owning through the participants to give or take the action or would otherwise act upon the instructions of beneficial owners holding through them.

We will make payments of principal and premium, if any, and interest, if any, on debt securities represented by a registered global security registered in the name of a depositary or its nominee to the depositary or its nominee, as the case may be, as the registered owners of the registered global security. Neither we nor the trustee, or any other agent of ours or the trustee will be responsible or liable for any aspect of the records relating to, or payments made on account of, beneficial ownership interests in the registered global security or for maintaining, supervising or reviewing any records relating to the beneficial ownership interests.

We expect that the depositary for any debt securities represented by a registered global security, upon receipt of any payments of principal and premium, if any, and interest, if any, in respect of the registered global security, will credit participants’ accounts with payments in amounts proportionate to their respective beneficial interests in the registered global security as shown on the records of the depositary. We also expect that standing customer instructions and customary practices will govern payments by participants to owners of beneficial interests in the registered global security held through the participants, as is now the case with the securities held for the accounts of customers in bearer form or registered in “street name.” We also expect that any of these payments will be the responsibility of the participants.

If the depositary for any debt securities represented by a registered global security is at any time unwilling or unable to continue as depositary or stops being a clearing agency registered under the Securities Exchange Act of 1934, as amended, we will appoint an eligible successor depositary. If we fail to appoint an eligible successor depositary within 90 days, we will issue the debt securities in definitive form in exchange for the registered global security. In addition, we may at any time and in our sole discretion decide not to have any of the debt securities of a series represented by one or more registered global securities. In that event, we will issue debt securities of the series in a definitive form in exchange for all of the registered global securities representing the debt securities. The trustee will register any debt securities issued in definitive form in exchange for a registered global security in the name or names as the depositary, based upon instructions from its participants, shall instruct the trustee.

We may also issue bearer debt securities of a series in the form of one or more global securities, referred to as “bearer global securities.” We will deposit these securities with a depositary identified in the prospectus supplement relating to the series. The prospectus supplement relating to a series of debt securities represented by a bearer global security will describe the applicable terms and procedures. These will include the specific terms of the depositary arrangement and any specific procedures for the issuance of debt securities in definitive form in exchange for a bearer global security, in proportion to the series represented by a bearer global security.

The indenture provides that there may be more than one trustee under the indenture, each for one or more series of debt securities. If there are different trustees for different series of debt securities, each trustee will be a trustee of a trust under the indenture separate and apart from the trust administered by any other trustee under that indenture. Except as otherwise indicated in this prospectus or any prospectus supplement, any action permitted to be taken by a trustee may be taken by such trustee only on the one or more series of debt securities for which it is the trustee under the indenture. Any trustee under the indenture may resign or be removed from one or more series of debt securities. All payments of principal of, and any premium and interest on, and all registration, transfer, exchange, authentication and delivery of, the debt securities of a series will be effected by the trustee for that series at an office designated by the trustee.

The indenture provides that, except during the continuance of an event of default, the trustee will perform only such duties as are specifically set forth in the indenture. During the existence of an event of default, the trustee will exercise those rights and powers vested in it under the indenture and use the same degree of care and skill in its exercise as a prudent person would exercise under the circumstances in the conduct of such person’s own affairs.

If the trustee becomes a creditor of ours, the indenture places limitations on the right of the trustee to obtain payment of claims or to realize on property received in respect of any such claim as security or otherwise. The trustee may engage in other transactions. If it acquires any conflicting interest relating to any duties concerning the debt securities, however, it must eliminate the conflict or resign as trustee.

The indenture provides that no past, present or future director, officer, stockholder or employee of ours, any of our affiliates, or any successor corporation, in their capacity as such, shall have any individual liability for any of our obligations, covenants or agreements under the debt securities or the indenture.

The indenture and the debt securities will be governed by, and construed in accordance with, the laws of the State of California.

We may issue warrants for the purchase of shares of our common stock or preferred stock or of debt securities. We may issue warrants independently or together with other securities, and the warrants may be attached to or separate from any offered securities. If a series of warrants will be issued under a separate warrant agreement to be entered into between us and the investors or a warrant agent, we will so specify in the applicable prospectus supplement. The following summary of the material provisions of the warrants and warrant agreements is subject to, and qualified in its entirety by reference to, all the provisions of the warrants and any warrant agreement applicable to a particular series of warrants. The terms of any warrants offered under a prospectus supplement may differ from the terms described below. We urge you to read the applicable prospectus supplement, as well as the complete warrants and warrant agreements that contain the terms of the warrants.

The material terms of any issue of warrants will be described in the prospectus supplement relating to the issue. Those terms may include:

Each warrant will entitle its holder to purchase the principal amount of debt securities or the number of shares of preferred stock or common stock at the exercise price set forth in, or calculable as set forth in, the applicable prospectus supplement. Unless we otherwise specify in the applicable prospectus supplement, holders of the warrants may exercise the warrants at any time up to the specified time on the expiration date that we set forth in the applicable prospectus supplement. After the close of business on the expiration date, unexercised warrants will become void.

A holder of warrant certificates may exchange them for new warrant certificates of different denominations, present them for registration of transfer and exercise them at the corporate trust office of the warrant agent or any other office indicated in the applicable prospectus supplement. Until any warrants to purchase debt securities are exercised, the holder of the warrants will not have any rights of holders of the debt securities that can be purchased upon exercise, including any rights to receive payments of principal, premium or interest on the underlying debt securities or to enforce covenants in the applicable indenture. Until any warrants to purchase common stock or preferred stock are exercised, the holders of the warrants will not have any rights of holders of the underlying common stock or preferred stock, including any rights to receive dividends or payments upon any liquidation, dissolution or winding up on the common stock or preferred stock, if any.

We may issue units consisting of any combination of the other types of securities offered under this prospectus in one or more series. We may elect to evidence each series of units by unit certificates that we will issue under a separate unit agreement. We may enter into unit agreements with a unit agent. Each unit agent will be a bank or trust company that we select. We will indicate the name and address of the unit agent in the applicable prospectus supplement relating to a particular series of units.

The following description, together with the additional information included in any applicable prospectus supplement, summarizes the general features of the units that we may offer under this prospectus. You should read any prospectus supplement related to the series of units being offered, as well as the complete unit agreements that contain the terms of the units. Specific unit agreements will contain additional important terms, and we will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from another report that we file with the SEC, the form of each unit agreement relating to units offered under this prospectus.

If we offer any units, certain terms of that series of units will be described in the applicable prospectus supplement, including, without limitation, the following, as applicable:

We may sell the securities covered by this prospectus from time to time pursuant to underwritten public offerings, negotiated transactions, block trades or a combination of these methods or through underwriters or dealers, through agents and/or directly to one or more purchasers. The securities may be distributed from time to time in one or more transactions:

Each time that we sell securities covered by this prospectus, we will provide a prospectus supplement or supplements that will describe the method of distribution and set forth the terms and conditions of the offering of such securities, including the offering price of the securities and the proceeds to us, if applicable.

Offers to purchase the securities being offered by this prospectus may be solicited directly. Agents may also be designated to solicit offers to purchase the securities from time to time. Any agent involved in the offer or sale of our securities will be identified in a prospectus supplement.

If a dealer is utilized in the sale of the securities being offered by this prospectus, the securities will be sold to the dealer, as principal. The dealer may then resell the securities to the public at varying prices to be determined by the dealer at the time of resale.

If an underwriter is utilized in the sale of the securities being offered by this prospectus, an underwriting agreement will be executed with the underwriter at the time of sale and the name of any underwriter will be provided in the prospectus supplement that the underwriter will use to make resales of the securities to the public. In connection with the sale of the securities, we or the purchasers of securities for whom the underwriter may act as agent, may compensate the underwriter in the form of underwriting discounts or commissions. The underwriter may sell the securities to or through dealers, and those dealers may receive compensation in the form of discounts, concessions or commissions from the underwriters and/or commissions from the purchasers for which they may act as agent. Unless otherwise indicated in a prospectus supplement, an agent will be acting on a best efforts basis and a dealer will purchase securities as a principal, and may then resell the securities at varying prices to be determined by the dealer.

Any compensation paid to underwriters, dealers or agents in connection with the offering of the securities, and any discounts, concessions or commissions allowed by underwriters to participating dealers, will be described in the applicable prospectus supplement. Underwriters, dealers and agents participating in the distribution of the securities may be deemed to be underwriters within the meaning of the Securities Act of 1933, as amended (the “Securities Act”), and any discounts and commissions received by them and any profit realized by them on resale of the securities may be deemed to be underwriting discounts and commissions. We may enter into agreements to indemnify underwriters, dealers and agents against civil liabilities, including liabilities under the Securities Act, or to contribute to payments they may be required to make in respect thereof and to reimburse those persons for certain expenses.

Any common stock issued by us will be traded on the OTCQB unless we specify otherwise in the prospectus supplement, but any other securities may or may not be publicly traded or listed on a national securities exchange. To facilitate the offering of securities, certain persons participating in the offering may engage in transactions that stabilize, maintain or otherwise affect the price of the securities. This may include over-allotments or short sales of the securities, which involve the sale by persons participating in the offering of more securities than were sold to them. In these circumstances, these persons would cover such over-allotments or short positions by making purchases in the open market or by exercising their over-allotment option, if any. In addition, these persons may stabilize or maintain the price of the securities by bidding for or purchasing securities in the open market or by imposing penalty bids, whereby selling concessions allowed to dealers participating in the offering may be reclaimed if securities sold by them are repurchased in connection with stabilization transactions. The effect of these transactions may be to stabilize or maintain the market price of the securities at a level above that which might otherwise prevail in the open market. These transactions may be discontinued at any time.

If indicated in the applicable prospectus supplement, underwriters or other persons acting as agents may be authorized to solicit offers by institutions or other suitable purchasers to purchase the securities at the public offering price set forth in the prospectus supplement, pursuant to delayed delivery contracts providing for payment and delivery on the date or dates stated in the prospectus supplement. These purchasers may include, among others, commercial and savings banks, insurance companies, pension funds, investment companies and educational and charitable institutions. Delayed delivery contracts will be subject to the condition that the purchase of the securities covered by the delayed delivery contracts will not at the time of delivery be prohibited under the laws of any jurisdiction in the United States to which the purchaser is subject. The underwriters and agents will not have any responsibility with respect to the validity or performance of these contracts.

We may engage in at-the-market offerings into an existing trading market in accordance with Rule 415(a)(4) under the Securities Act. In addition, we may enter into derivative transactions with third parties, or sell securities not covered by this prospectus to third parties in privately negotiated transactions. If the applicable prospectus supplement so indicates, in connection with those derivatives, the third parties may sell securities covered by this prospectus and the applicable prospectus supplement, including in short sale transactions. If so, the third party may use securities pledged by us or borrowed from us or others to settle those sales or to close out any related open borrowings of stock, and may use securities received from us in settlement of those derivatives to close out any related open borrowings of stock. The third party in such sale transactions will be an underwriter and, if not identified in this prospectus, will be named in the applicable prospectus supplement. In addition, we may otherwise loan or pledge securities to a financial institution or other third party that in turn may sell the securities short using this prospectus and an applicable prospectus supplement. Such financial institution or other third party may transfer its economic short position to investors in our securities or in connection with a concurrent offering of other securities.

The specific terms of any lock-up provisions in respect of any given offering will be described in the applicable prospectus supplement.

In compliance with the guidelines of the Financial Industry Regulatory Authority, Inc. (“FINRA”), the maximum consideration or discount to be received by any FINRA member or independent broker dealer may not exceed 8% of the aggregate proceeds of the offering.

The underwriters, dealers and agents may engage in transactions with us, or perform services for us, in the ordinary course of business for which they receive compensation.

TroyGould PC, Los Angeles, California, has issued an opinion about certain matters with respect to the securities offered by this prospectus. Additional legal matters may be passed upon for us, or for any underwriters, dealers or agents, by counsel that we name in the applicable prospectus supplement.

The consolidated financial statements of Sigma Labs, Inc. as of December 31, 2013 and 2012 and for the years then ended, which are incorporated into this prospectus by reference to our Annual Report on Form 10-K for the year ended December 31, 2013, have been so incorporated in reliance on the report of Pritchett, Siler & Hardy, P.C., an independent registered public accounting firm, upon the authority of said firm as experts in auditing and accounting.

We are subject to the information and periodic reporting requirements of the Securities Exchange Act of 1934, as amended (the "Exchange Act") and, in accordance with that act, file periodic reports and other information with the SEC. The periodic reports and other information filed by us are available for inspection and copying at prescribed rates at the SEC’s Public Reference Room at 100 F Street, N.E., Washington, D.C. 20549. Please call the SEC at 1-800-SEC-0330 for further information about the operation of the SEC’s Public Reference Room. The SEC also maintains an Internet site that contains all reports and other information that we file electronically with the SEC. The address of that website is www.sec.gov.

This prospectus is part of a registration statement on Form S-3 that we have filed with the SEC under the Securities Act for the securities offered under this prospectus (the "Form S-3 Registration Statement"). The Form S-3 Registration Statement, including the exhibits to the Form S-3 Registration Statement, contains additional information about us and the securities offered by this prospectus. The rules and regulations of the SEC allow us to omit from this prospectus certain information that is included in the Form S-3 Registration Statement. For further information about us and our securities, you should review the Form S-3 Registration Statement and the exhibits filed with the Form S-3 Registration Statement.

The SEC allows us to incorporate into this prospectus by reference the information we file with it, which means that we can disclose important information to you by referring you to the documents containing that information. The information incorporated by reference is considered to be part of this prospectus, and information that we later file with the SEC will automatically update and, where applicable, modify or supersede that information.

We incorporate by reference into this prospectus the following documents that we have filed, or will file, with the SEC:

You may request a copy of any of these filings from us at no cost by writing or calling our Chief Executive Officer at the following address or telephone number: Sigma Labs, Inc.; 3900 Paseo del Sol, Santa Fe, New Mexico 87507; (505) 438-2576.

Notwithstanding the foregoing, no portion of any document that is “furnished” but not “filed” in accordance with SEC rules under Exchange Act shall be deemed to be incorporated by reference into the Form S-3 Registration Statement. Any statement contained in the Form S-3 Registration Statement or in a document incorporated by reference into the Form S-3 Registration Statement will be deemed to be modified or superseded for purposes of the Form S-3 Registration Statement to the extent that a statement contained in the Form S-3 Registration Statement or in any other subsequently filed document that is incorporated by reference into the Form S-3 Registration Statement modifies or supersedes the statement. Any statement so modified or superseded will not be deemed, except as so modified or superseded, to constitute a part of the Form S-3 Registration Statement.

We have entered into an At The Market Offering Agreement (the “sales agreement”) with Ascendiant Capital Markets, LLC (“Ascendiant”) relating to the shares of our common stock offered by this at-the-market offering prospectus and the accompanying base prospectus. In accordance with the terms of the sales agreement, we may offer and sell shares of our common stock having an aggregate offering price of up to $25,000,000 from time to time through Ascendiant as our sales agent.

Our common stock is traded on the OTCQB under the symbol “SGLB.” On December 16, 2014, the last reported sale price of our common stock on the OTCQB was $0.0745 per share.

Sales of our common stock under this at-the-market offering prospectus and the accompanying base prospectus, may be made in sales deemed to be “at-the-market” equity offerings as defined in Rule 415 promulgated under the Securities Act of 1933, as amended (the “Securities Act”), including sales made directly on or through the OTCQB, sales made to or through a market maker other than on the OTCQB or otherwise, in negotiated transactions at market prices prevailing at the time of sale or at prices related to such prevailing market prices and/or any other method permitted by law, provided that, pursuant to the terms of the sales agreement, until our common stock is listed on a national securities exchange, sales in this at-the-market offering may be made only in one or more privately negotiated transactions that are eligible for an exemption from registration under the applicable state securities laws. Under the terms of the sales agreement, we may also sell shares to Ascendiant as principal for its own account. Ascendiant is not required to sell any specific number or dollar amount of common stock but will act as a sales agent using commercially reasonable efforts consistent with its normal trading and sales practices and on mutually agreed terms between Ascendiant and us. There is no arrangement for funds to be received in any escrow, trust or similar arrangement.

The compensation to Ascendiant for sales of common stock sold pursuant to the sales agreement will be 3% of the gross proceeds of any shares of common stock sold under the sales agreement. Other compensation may apply when Ascendiant purchases shares as principal at a price agreed by us and Ascendiant. As described in this at the market offering prospectus under “Plan of Distribution” beginning on page S-9, we have agreed to reimburse certain expenses of Ascendiant in connection with the sales agreement. In connection with the sale of the common stock on our behalf, Ascendiant will be deemed to be an “underwriter” within the meaning of the Securities Act and the compensation of Ascendiant will be deemed to be underwriting commissions or discounts. We have also agreed to provide indemnification and contribution to Ascendiant with respect to certain liabilities, including liabilities under the Securities Act or the Securities Exchange Act of 1934, as amended (the “Exchange Act”).

An investment in our common stock involves a high degree of risk. See “Risk Factors” beginning on page S-4 of this at-the-market offering prospectus and page 3 of the accompanying prospectus for a discussion of risks that you should consider before you invest in our common stock.

This at-the-market offering prospectus is a part of a registration statement on Form S-3 that we filed with the Securities and Exchange Commission (the “SEC”) utilizing a “shelf” registration process. Under the shelf registration process, we may sell shares of our common stock having an aggregate offering price of up to $25,000,000 from time to time under this at-the-market offering prospectus at prices and on terms to be determined by market conditions at the time of each offering.

This document is comprised of two parts. The first part is the accompanying base prospectus (including the documents incorporated by reference into the accompanying base prospectus), which provides general information about us and our securities, some of which may not apply to this offering. The second part is this at-the-market offering prospectus, which describes the specific terms of this offering and also adds to, and updates information contained in, the accompanying base prospectus and the documents incorporated by reference into this at-the-market offering prospectus and the accompanying base prospectus.

Generally, when we refer to this “prospectus,” we are referring to the combined document consisting of this at-the-market offering prospectus and the accompanying base prospectus. If information in this at-the-market offering prospectus is inconsistent with the accompanying base prospectus or with any document incorporated by reference into this at-the-market offering prospectus or the base prospectus that was filed before the date of this at-the-market-offering prospectus, you should rely on this prospectus. However, if any statement in one of these documents is inconsistent with a statement in another document having a later date, for example, a future filing incorporated by reference into this prospectus, the statement in the document having the later date modifies or supersedes the earlier statement as our business, financial condition, results of operations and prospects may have changed since the earlier dates.

You should rely only on the information contained in, or incorporated by reference into, this at-the-market offering prospectus, the accompanying base prospectus and any free writing prospectuses that we authorize for use in connection with this offering. We have not authorized any other person to provide you with different information. We are not making an offer to sell or soliciting an offer to buy our securities in any jurisdiction in which an offer or solicitation is not authorized or in which the person making that offer or solicitation is not qualified to do so or to anyone to whom it is unlawful to make an offer or solicitation.

You should assume that the information appearing in this at-the-market offering prospectus, the accompanying base prospectus, the documents incorporated by reference into this at-the-market offering prospectus and the accompanying base prospectus and any free writing prospectuses that we authorize for use in connection with this offering is accurate only as of the date of those respective documents. Our business, financial condition, results of operations and prospects may have changed since those dates.

You should read this at-the-market offering prospectus, the accompanying base prospectus, the documents incorporated by reference into this at-the-market offering prospectus and the accompanying base prospectus and any free writing prospectuses that we authorize for use in connection with this offering in their entirety before making an investment decision. You should also read and consider the information in the documents to which we have referred you in the sections of this at-the-market offering prospectus entitled “Where You Can Find More Information” and “Incorporation of Certain Information by Reference.” The information incorporated by reference is considered part of this at-the-market offering prospectus, and information we file later with the SEC may automatically update and supersede this information.

References in this at-the-market offering prospectus to “Sigma Labs,” “we,” “us” and “our” refer to Sigma Labs, Inc. and its subsidiaries.”

AT-THE-MARKET OFFERING PROSPECTUS SUMMARY

This summary highlights certain information about us, this offering and selected information contained elsewhere in or incorporated by reference into this at-the-market offering prospectus. This summary is not complete and does not contain all of the information that you should consider before deciding whether to invest in our common stock. For a more complete understanding of our company and this offering, we encourage you to read and consider carefully this entire at-the-market offering prospectus, the accompanying base prospectus, any free writing prospectuses that we authorize for use in connection with this offering and the documents incorporated by reference into this at-the-market offering prospectus and the accompanying base prospectus, including the information under the heading “Risk Factors” in this at-the-market offering prospectus beginning on page S-4, in the accompanying base prospectus on page 3 and in the documents incorporated by reference into this at-the-market offering prospectus.

Sigma Labs

identify, develop and commercialize manufacturing and materials technologies designed to improve manufacturing and quality control practices, and create innovative products in a variety of industries; and

provide engineering consulting services in respect of our manufacturing and materials technology expertise to third parties that have needs in developing next-generation technologies for materials and manufacturing projects.

We are presently engaged in a variety of activities in which we seek to commercialize technologies and products in the following industry sectors:

aerospace and defense manufacturing;

oil and gas manufacturing;

bio-medical manufacturing; and

automotive manufacturing.

THE OFFERING

Common stock offered by us	Shares of our common stock having an aggregate offering price of up to $25,000,000.

Common stock to be outstanding after this offering	Assuming that all $25,000,000 of our common stock is sold pursuant to this at-the-market offering prospectus at an assumed offering price of $0.0745 per share, which was the last reported sale price of our common stock on the OTCQB on December 16, 2014, we would have 955,311,531 shares of common stock outstanding.

Manner of offering	“At-the-market” offering that may be made from time to time through our sales agent, Ascendiant. See “Plan of Distribution” beginning on page S-9 of this at-the-market offering prospectus.

Use of proceeds	We intend to use the net proceeds from the sale of the common stock described in this at-the-market offering prospectus for general corporate purposes which may include, among other things, reducing indebtedness, acquiring other businesses (although we currently have no agreement to acquire any business), repurchasing our common stock and making capital expenditures, as well as for working capital. See “Use of Proceeds” on page S-6 of this at-the-market offering prospectus.

Risk factors	Investing in our common stock involves a high degree of risk. See “Risk Factors” beginning on page S-4 of this at-the-market offering prospectus.

OTCQB symbol	SGLB

The number of shares of our common stock to be issued and outstanding immediately after this offering as shown above is based on 619,741,061 shares issued and outstanding as of December 18, 2014, and excludes as of that date:

18,796,296 shares of common stock issuable upon the exercise of outstanding warrants having a weighted average exercise price of $0.141 per share;

an aggregate of 21,400,000 shares of common stock reserved for future issuance under our equity incentive plans.

Investing in our common stock involves a high degree of risk. Before making an investment decision, you should carefully consider the risks relating to this offering and our common stock described below, together with the risks described under “Risk Factors” in our most recent Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q and the other information incorporated by reference into this at-the-market offering prospectus, together with the information in any free writing prospectuses that we may authorize for use in connection with this offering. If any of these risks were to occur, our business, financial condition, results of operations, cash flows or prospects could be materially and adversely affected. In such case, you may lose all or part of your investment.

The risks described below and in our most recent Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q are not the only ones facing us. Additional risks and uncertainties not presently known to us or that we currently deem immaterial may also materially and adversely affect our business and operations.

The market price of our common stock has exhibited substantial volatility. Between January 1, 2013 and December 16, 2014, the sale price of our common stock as reported on the OTCQB ranged from a low of $0.0125 to a high of $0.276. The market price of our common stock could continue to fluctuate significantly for many reasons, including the following factors:

In addition, factors beyond our control may also have an impact on the price of our common stock. For example, to the extent that other large companies within our industry experience declines in their stock price, our stock price may decline as well. In addition, when the market price of a company’s common stock drops significantly, security holders often institute securities class action lawsuits against the company. A lawsuit against us could cause us to incur substantial costs and could divert the time and attention of our management and other resources.

Future sales of substantial amounts of our common stock, or the possibility that such sales could occur, could adversely affect the market price of our common stock.

Future sales in the public market of our common stock, including shares offered by this at-the-market offering prospectus, or the perception by the market that these issuances or sales could occur, could lower the market price of our common stock or make it difficult for us to raise additional capital. As of December 16, 2014, we had 619,741,061 shares of common stock issued and outstanding, substantially all of which may be sold publicly, subject in some cases to volume and other limitations or prospectus delivery requirements.

We may issue preferred stock in the future, and the terms of the preferred stock may reduce the value of our common stock.

We are authorized to issue up to 10,000,000 shares of preferred stock in one or more series. Our board of directors may determine the terms of future preferred stock offerings without further action by our stockholders. If we issue preferred stock, it could affect your rights or reduce the market value of our outstanding common stock. In particular, specific rights granted to future holders of preferred stock may include voting rights, preferences as to dividends and liquidation, conversion and redemption rights, sinking fund provisions, and restrictions on our ability to merge with or sell our assets to a third party.

We have never declared or paid cash dividends on our capital stock and we do not anticipate paying cash dividends in the foreseeable future.

Our business requires significant funding. We currently plan to invest all available funds and future earnings in the development and growth of our business and do not anticipate paying any cash dividends on our common stock in the foreseeable future. As a result, capital appreciation, if any, of our common stock will be our stockholders’ sole source of potential gain for the foreseeable future.

Management will have broad discretion as to the use of the net proceeds of this offering, and we may not use the net proceeds effectively or in a manner that is acceptable to our stockholders.

We intend to use the net proceeds from the sale of the common stock described in this at-the-market offering prospectus for general corporate purposes which may include, among other things, reducing indebtedness, acquiring other businesses (although we currently have no agreement to acquire any business), repurchasing our common stock and making capital expenditures, as well as for working capital. We have not reserved or allocated amounts for any specific purposes, however, and we cannot specify with certainty how we will use any net proceeds. Accordingly, our management will have considerable discretion in the application of the net proceeds, and you will not have the opportunity, as part of your investment decision, to assess whether the proceeds are being used appropriately. The net proceeds may be used for corporate purposes that do not benefit our company or increase our market value. Until the net proceeds are used, they may be placed in investments that may not produce income or that may lose value.

Investors in this offering will experience immediate and substantial dilution in the book value of their shares.

Investors in this offering will suffer immediate and substantial dilution in the book value of their shares. See “Dilution” on page 7 of this prospectus for more information about the dilution that you will incur in this offering.

This at-the-market offering prospectus, the accompanying base prospectus and the documents that are incorporated by reference herein and therein contain forward-looking statements. These statements relate to future events or to our future financial performance and involve known and unknown risks, uncertainties and other factors that may cause our actual results to be materially different from any future results expressed or implied by the forward-looking statements. In some cases, you can identify forward-looking statements by the use of words such as “believe,” “anticipate,” “intend,” “plan,” “estimate,” “may,” “could,” “anticipate,” “predict,” or “expect” and similar expressions. You should not place undue reliance on forward-looking statements since they involve known and unknown risks, uncertainties and other factors that are, in many cases, beyond our control. Forward-looking statements are not guarantees of future performance. Actual events or results may differ materially from those discussed in the forward-looking statements as a result of various factors. Except as required by applicable law, we do not undertake any obligation to publicly update any forward-looking statements, whether as a result of new information, future developments or otherwise.

We discuss certain of these risks and uncertainties in greater detail in this at-the-market offering prospectus under the heading “Risk Factors” beginning on page S-4. Additional cautionary statements or discussions of risks and uncertainties that could affect our results or the achievement of the expectations described in forward-looking statements are contained in our most recent Annual Report on Form 10-K filed with the SEC and our Quarterly Reports on Form 10-Q filed subsequently with the SEC.

If we receive all $25,000,000 of gross proceeds from the sale of the shares of common stock offered by this at-the-market offering prospectus, we anticipate that the net proceeds that we will receive from this offering will be approximately $24,100,000, after deducting the estimated commissions payable to Ascendiant and estimated offering expenses payable by us. The exact amount of net proceeds that we will receive from this offering will depend upon the number of shares of our common stock, if any, that are issued and the price or prices at which the shares are sold. There is no assurance regarding the number of shares, if any, that we will be able to issue under the sales agreement with Ascendiant.

We intend to use the net proceeds from the sale of the common stock described in this at-the-market offering prospectus for general corporate purposes which may include, among other things, reducing indebtedness, acquiring other businesses (although we currently have no agreement to acquire any business), repurchasing our common stock and making capital expenditures, as well as for working capital. Until we use the net proceeds for these purposes, we intend to invest the net proceeds in investment-grade, interest-bearing securities. We have not determined the amounts we plan to spend on any of these areas or the timing of these expenditures. As a result, our management will have broad discretion regarding the application of the net proceeds from the sale of the common stock described in this at-the-market offering prospectus.

If you invest in our common stock in this offering, your ownership interest will be diluted immediately to the extent of the difference between the amount per share paid by purchasers and the pro forma net tangible book value per share of our common stock after this offering.

Our historical net tangible book value as of September 30, 2014 was approximately $ 4,029,468, or $0.0065 per share of common stock. Historical net tangible book value per share is calculated by subtracting our total liabilities from our total tangible assets, which is total assets less intangible assets, and dividing this amount by the number of shares of common stock outstanding.

After giving effect to the assumed sale of 335,570,470 shares of our common stock by us in this offering in the aggregate amount of $25,000,000 at an assumed offering price of $0.0745 per share, which was the last reported sale price of our common stock on the OTCQB on December 16, 2014, and after deducting estimated offering commissions and expenses payable by us, we would have had a pro forma net tangible book value as of September 30, 2014 of approximately $28,129,468, or $0.029 per share of common stock. This represents an immediate increase in the pro forma net tangible book value of $0.023 per share to our existing stockholders and an immediate dilution in pro forma net tangible book value of $0.045 per share to new investors purchasing common stock in this offering.

Dilution per share to new investors is determined by subtracting pro forma net tangible book value per share after this offering from the public offering price per share paid by new investors. The following table illustrates this dilution on a per share basis:

Each $0.01 increase (decrease) in the assumed public offering price of $0.0745 per share (the last reported sale price of our common stock on the OTCQB on December 16, 2014), assuming all of our common stock in the aggregate amount of $25,000,000 is sold at that price, would increase (decrease) our pro forma net tangible book value per share after this offering by approximately $0.0013 per share, and the dilution per share to new investors by approximately $0.009 per share, after deducting the estimated sales commissions and estimated offering expenses payable by us. The information discussed above is illustrative only and will adjust based upon the actual public offering price and the actual number of shares that we sell in this offering.

The number of shares of our common stock to be outstanding immediately after this offering as shown above is based on 618,241,061 shares outstanding as of September 30, 2014 and excludes as of that date:

To the extent that warrants outstanding as of September 30, 2014 have been or may be exercised or other shares issued, investors purchasing our common stock in this offering may experience further dilution. In addition, we may choose to raise additional capital due to market conditions or strategic considerations even if we believe we have sufficient funds for our current or future operating plans. To the extent that additional capital is raised through the sale of equity or convertible debt securities, the issuance of these securities could result in further dilution to investors purchasing our common stock in this offering.

We have authority to issue 750,000,000 shares of common stock, par value $0.001 per share. As of December 16, 2014, 619,741,061 shares of our common stock were issued and outstanding and there were outstanding warrants to purchase 18,796,296 shares of our common stock. The following summary of our common stock is qualified by reference to the provisions of our articles of incorporation and bylaws, which are filed as exhibits to the Form S-3 registration statement of which this at-the-market offering prospectus is a part.

We have entered into an At The Market Offering Agreement (the “sales agreement”), with Ascendiant Capital Markets, LLC (“Ascendiant”) under which we may issue and sell shares of our common stock having aggregate sales proceeds of up to $25,000,000 from time to time through Ascendiant acting as agent. Ascendiant may sell the common stock by any method that is deemed to be an “at-the-market” equity offering as defined in Rule 415 promulgated under the Securities Act, including sales made directly on or through the OTCQB or any other existing trading market for our common stock in the United States or to or through a market maker, provided that, pursuant to the terms of the sales agreement, until our common stock is listed on a national securities exchange, sales in this at-the-market offering may be made only in one or more privately negotiated transactions that are eligible for an exemption from registration under the applicable state securities laws. Under the terms of the sales agreement, we may also sell shares to Ascendiant as principal for its own account. Ascendiant also may sell the common stock in privately negotiated transactions.

Each time we wish to issue and sell common stock under the sales agreement, we will notify Ascendiant of the maximum number of shares to be sold, the dates on which such sales are anticipated to be made and any minimum price below which sales may not be made. Once we have so instructed Ascendiant, Ascendiant has agreed to use its commercially reasonable efforts consistent with its normal trading and sales practices to sell such shares up to the amount specified on such terms. The obligations of Ascendiant under the sales agreement to sell our common stock are subject to a number of conditions that we must meet.

Ascendiant will provide written confirmation to us following the close of trading on the OTCQB following each day in which shares of our common stock are sold under the sales agreement. Each confirmation will include the number of shares sold on the day, the aggregate gross sales proceeds, the net proceeds to us and the compensation payable by us to Ascendiant with respect to the sales. The settlement between us and Ascendiant is generally anticipated to occur on the third trading day following the date on which the sale was made. Sales of our common stock as contemplated in this at-the-market offering prospectus will be settled through the facilities of The Depository Trust Company or by such other means as we and Ascendiant may agree. There is no arrangement for funds to be received in an escrow, trust or similar arrangement.

We will pay Ascendiant a commission equal to 3% of the gross proceeds we receive from the sales of our common stock. Because there is no minimum offering amount required as a condition of this offering, the actual total public offering amount, commissions and proceeds to us, if any, are not determinable at this time. In connection with the sale of the common stock on our behalf, Ascendiant will be deemed to be an “underwriter” within the meaning of the Securities Act, and the compensation of Ascendiant will be deemed to be underwriting commissions or discounts. We have also agreed to reimburse Ascendiant for its legal and due diligence expenses up to an aggregate amount not to exceed $80,000, subject to compliance with FINRA Rule 5110(f)(2)(D). We have agreed to provide indemnification and contribution to Ascendiant with respect to certain civil liabilities, including liabilities under the Securities Act. We estimate that the total expenses for the offering, excluding commissions payable to Ascendiant under the terms of the sales agreement, will be approximately $150,000, including expense reimbursements under the sales agreement of $80,000.

The offering of our common stock pursuant to the sales agreement will terminate upon the earliest of (1) the sale of all of our common stock provided for in this at-the-market offering prospectus, (2) termination of the sales agreement as permitted therein, or (3) the two- year anniversary of the date of the sales agreement. The sales agreement may be terminated by us at any time upon at least five days prior written notice to Ascendiant.

This summary of the material provisions of the sales agreement does not purport to be a complete statement of its terms and conditions. A copy of the sales agreement is filed with the SEC and is incorporated by reference into the registration statement of which this at-the-market offering prospectus is a part. See “Where You Can Find More Information” below.

To the extent required by Regulation M, Ascendiant will not engage in any market making activities involving our common stock while the offering is ongoing under this at- the - market offering prospectus.

TroyGould PC, Los Angeles, California, has issued an opinion about certain matters with respect to the securities offered by this at-the-market offering prospectus. Ellenoff Grossman & Schole LLP, New York, New York, is counsel for Ascendiant in connection with this offering.

The consolidated financial statements of Sigma Labs, Inc. as of December 31, 2013 and 2012 and for the years then ended, which are incorporated into this at-the-market offering prospectus by reference to our Annual Report on Form 10-K for the year ended December 31, 2013, have been so incorporated in reliance on the report of Pritchett, Siler & Hardy, P.C., an independent registered public accounting firm, upon the authority of said firm as experts in auditing and accounting.

This at-the-market offering prospectus is part of a registration statement on Form S-3 that we have filed with the SEC under the Securities Act for the securities offered under this at-the-market offering prospectus (the "Form S-3 Registration Statement"). The Form S-3 Registration Statement, including the exhibits to the Form S-3 Registration Statement, contains additional information about us and the securities offered by this at-the-market offering prospectus. The rules and regulations of the SEC allow us to omit from this at- the - market offering prospectus certain information that is included in the Form S-3 Registration Statement. For further information about us and our securities, you should review the Form S-3 Registration Statement and the exhibits filed with the Form S-3 Registration Statement.

The SEC allows us to incorporate into this at-the-market offering prospectus by reference the information we file with it, which means that we can disclose important information to you by referring you to the documents containing that information. The information incorporated by reference is considered to be part of this at-the-market offering prospectus, and information that we later file with the SEC will automatically update and, where applicable, modify or supersede that information.

We incorporate by reference into this at-the-market offering prospectus the following documents that we have filed, or will file, with the SEC:

The following table sets forth the expenses to be paid by us, other than underwriting discounts and commissions, in connection with the offering of the securities described in this registration statement. All amounts shown are estimates except for the Securities and Exchange Commission registration fee and FINRA filing fee.

Pursuant to our amended and restated articles of incorporation, none of our directors or officers will have any personal liability to us or our stockholders for damages for breach of fiduciary duty as a director or officer, except for damages for breach of fiduciary duty resulting from (1) acts or omissions which involve intentional misconduct, fraud or a knowing violation of law or (2) the payment of dividends in violation of the applicable statutes of Nevada.

Section 78.7502 of the Nevada Revised Statutes permits a corporation to indemnify a present or former director, officer, employee or agent of the corporation, or of another entity or enterprise for which such person is or was serving in such capacity at the request of the corporation, who was or is a party or is threatened to be made a party to any threatened, pending or completed action, suit or proceeding, except an action by or in the right of the corporation, against expenses, including attorneys’ fees, judgments, fines and amounts paid in settlement actually and reasonably incurred in connection therewith, arising by reason of such person’s service in such capacity if such person (1) is not liable pursuant to Section 78.138 of the Nevada Revised Statutes, which sets forth standards for the conduct of directors and officers, or (2) acted in good faith and in a manner which he or she reasonably believed to be in or not opposed to the best interests of the corporation and, with respect to a criminal action or proceeding, had no reasonable cause to believe his or her conduct was unlawful. In the case of actions brought by or in the right of the corporation, however, no indemnification may be made for any claim, issue or matter as to which such person has been adjudged by a court of competent jurisdiction, after exhaustion of all appeals therefrom, to be liable to the corporation or for amounts paid in settlement to the corporation, unless and only to the extent that the court in which the action or suit was brought or other court of competent jurisdiction determines upon application that in view of all the circumstances of the case, such person is fairly and reasonably entitled to indemnity for such expenses as the court deems proper.

Section 78.751 of the Nevada Revised Statutes permits any discretionary indemnification under Section 78.7502 of the Nevada Revised Statutes, unless ordered by a court or advanced to a director or officer by the corporation in accordance with the Nevada Revised Statutes, to be made by a corporation only as authorized in each specific case upon a determination that indemnification of the director, officer, employee or agent is proper in the circumstances. Such determination must be made (1) by the stockholders, (2) by the board of directors by majority vote of a quorum consisting of directors who were not parties to the action, suit or proceeding, (3) if a majority vote of a quorum consisting of directors who were not parties to the action, suit or proceeding so orders, by independent legal counsel in a written opinion, or (4) if a quorum consisting of directors who were not parties to the action, suit or proceeding cannot be obtained, by independent legal counsel in a written opinion.

Our amended and restated bylaws require us to indemnify our directors and officers in a manner that is consistent with the provisions of Nevada law described in the preceding two paragraphs.

We maintain a general liability insurance policy that covers certain liabilities of directors and officers of our corporation arising out of claims based on acts or omissions in their capacities as directors or officers. Furthermore, we have entered into indemnification agreements with our directors and officers that, among other things, indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers.

A list of exhibits filed with this Registration Statement on Form S-3 is set forth in the Exhibit Index and is incorporated by reference into this Item 16.

(1) To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

(i) To include any prospectus required by Section 10(a)(3) of the Securities Act of 1933;

(ii) To reflect in the prospectus any facts or events arising after the effective date of this registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in this registration statement; notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the Securities and Exchange Commission pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than a 20% change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement; and

(iii) To include any material information with respect to the plan of distribution not previously disclosed in this registration statement or any material change to such information in this registration statement; provided, however, that paragraphs (a)(1)(i), (a)(1)(ii) and (a)(1)(iii) do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the Securities and Exchange Commission by the registrant pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 that are incorporated by reference in this registration statement, or is contained in a form of prospectus filed pursuant to Rule 424(b) that is part of this registration statement.

(2) That, for the purpose of determining any liability under the Securities Act of 1933, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(3) To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

(4) That, for the purpose of determining liability under the Securities Act of 1933 to any purchaser:

(i) Each prospectus filed by the registrant pursuant to Rule 424(b)(3) shall be deemed to be part of this registration statement as of the date the filed prospectus was deemed part of and included in this registration statement; and

(ii) Each prospectus required to be filed pursuant to Rule 424(b)(2), (b)(5), or (b)(7) as part of a registration statement in reliance on Rule 430B relating to an offering made pursuant to Rule 415(a)(1)(i), (vii), or (x) for the purpose of providing the information required by Section 10(a) of the Securities Act of 1933 shall be deemed to be part of and included in this registration statement as of the earlier of the date such form of prospectus is first used after effectiveness or the date of the first contract of sale of securities in the offering described in the prospectus. As provided in Rule 430B, for liability purposes of the issuer and any person that is at that date an underwriter, such date shall be deemed to be a new effective date of this registration statement relating to the securities in this registration statement to which that prospectus relates, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof; provided, however, that no statement made in a registration statement or prospectus that is part of this registration statement or made in a document incorporated or deemed incorporated by reference into this registration statement or prospectus that is a part of this registration statement will, as to a purchaser with a time of contract sale prior to such effective date, supersede or modify any statement that was made in this registration statement or prospectus that was a part of this registration statement or made in any such document immediately prior to such effective date.

(5) That, for the purpose of determining liability of the registrant under the Securities Act of 1933 to any purchaser in the initial distribution of securities, the undersigned registrant undertakes that in a primary offering of securities of the undersigned registrant pursuant to this registration statement, regardless of the underwriting method used to sell the securities to the purchaser, if the securities are offered or sold to such purchaser by means of any of the following communications, the undersigned registrant will be a seller to the purchaser and will be considered to offer or sell such securities to such purchaser:

(i) Any preliminary prospectus or prospectus of the undersigned registrant relating to the offering required to be filed pursuant to Rule 424;

(ii) Any free writing prospectus relating to the offering prepared by or on behalf of the undersigned registrant or used or referred to by the undersigned registrant;

(iii) The portion of any other free writing prospectus relating to the offering containing material information about the undersigned registrant or its securities provided by or on behalf of the undersigned registrant; and

(iv) Any other communication that is an offer in the offering made by the undersigned registrant to the purchaser.

(b) The undersigned registrant hereby undertakes that, for purposes of determining any liability under the Securities Act of 1933, each filing of the registrant’s annual report pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934 and (and, where applicable, each filing of an employee benefit plan’s annual report pursuant to Section 15(d) of the Securities Exchange Act of 1934) that is incorporated by reference in this registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(c) Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Securities Act of 1933 and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act of 1933 and will be governed by the final adjudication of such issue.

(d) The undersigned registrant hereby undertakes to file an application for the purpose of determining the eligibility of the trustee to act under subsection (a) of Section 310 of the Trust Indenture Act (the “Act”) in accordance with the rules and regulations prescribed by the SEC under section 305(b)(2) of the Act.

Pursuant to the requirements of the Securities Act of 1933, the registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-3 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Santa Fe, New Mexico, on December 18, 2014.

Pursuant to the requirements of the Securities Act of 1933, this registration statement has been signed by the following persons in the capacities indicated on December 18, 2014.

Large accelerated filer	¨	Accelerated filer ¨
Non-accelerated filer	¨ (Do not check if a smaller reporting company)	Smaller reporting company x

Title of each class of securities to be registered	Amount to be registered (1)(2)	Proposed maximum offering price per unit (1)(2)	Proposed maximum aggregate offering price (2)		Amount of registration fee
Common Stock, $0.001 par value (3)						—
Preferred Stock, $0.001 par value (3)						—
Debt Securities (3)						—
Warrants						—
Units						—
Total			$	100,000,000	$	12,880	(2)

	Page

ABOUT THIS PROSPECTUS	1

SIGMA LABS	2

RISK FACTORS	3

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS	3

USE OF PROCEEDS	3

THE SECURITIES THAT WE MAY OFFER	4

DESCRIPTION OF COMMON STOCK	4

DESCRIPTION OF PREFERRED STOCK	5

DESCRIPTION OF DEBT SECURITIES	6

DESCRIPTION OF WARRANTS	15

DESCRIPTION OF UNITS	17

PLAN OF DISTRIBUTION	17

LEGAL MATTERS	19

EXPERTS	19

WHERE YOU CAN FIND MORE INFORMATION	20

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE	20

ABOUT THIS AT THE MARKET OFFERING PROSPECTUS	S-1

AT - THE - MARKET OFFERING PROSPECTUS SUMMARY	S-2

THE OFFERING	S-3

RISK FACTORS	S-4

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS	S-6

USE OF PROCEEDS	S-6

DIVIDEND POLICY	S-6

DILUTION	S-7

DESCRIPTION OF OUR COMMON STOCK	S-8

PLAN OF DISTRIBUTION	S-9

LEGAL MATTERS	S-10

EXPERTS	S-10

WHERE YOU CAN FIND MORE INFORMATION	S-10

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE	S-11


Securities and Exchange Commission registration fee	$	12,880
FINRA fee	$	15,500
Printing and engraving expenses		*
Legal fees and expenses		*
Accounting fees and expenses		*
Transfer agent and registrar fees		*
Miscellaneous expenses		*

Total	$	*

Assumed public offering price per share			$	0.0745
Net tangible book value per share as of September 30, 2014	$	0.0065
Increase in net tangible book value per share attributable to this offering		0.023
Pro forma net tangible book per share after this offering			$	0.029
Dilution per share to new investors purchasing shares in this offering			$	0.045

	SIGMA LABS, INC.

	By:	/s/ Mark J. Cola
		Mark J. Cola
		President and Chief Executive Officer

Signature		Title

/s/ Mark J. Cola
Mark J. Cola		President and Chief Executive Officer
		(Principal Executive Officer)

/s/ Monica Yaple		Treasurer
Monica Yaple		(Principal Financial and Accounting Officer)


*/s/ Thomas P. O'Mara		Director
Thomas P. O'Mara

*/s/ Michael M. Thacker		Director and Corporate Secretary
Michael M. Thacker

*By: /s/ Mark J. Cola		Attorney-in-fact
Mark J. Cola

Exhibit Number		Description of Document

1.1		At the Market Offering Agreement, dated as of September 23, 2014, between Sigma Labs, Inc. and Ascendiant Capital Markets, LLC (previously filed by the registrant on September 23, 2014 as Exhibit 1.1 to the registrant’s registration statement on Form S-3 and incorporated herein by reference).

1.2		Form of Underwriting Agreement.*
4.1		Amended and Restated Articles of Incorporation of Sigma Labs, Inc. (previously filed by the registrant on September 17, 2010 as Exhibit 3.1 to the registrant’s Current Report on Form 8-K/A and incorporated herein by reference).

4.2		Certificate of Correction to Amended and Restated Articles of Incorporation of Sigma Labs, Inc. (previously filed by the registrant on June 1, 2011 as Exhibit 3.2 to the registrant’s Current Report on Form 8-K and incorporated herein by reference).

4.3		Amended and Restated Bylaws of Sigma Labs, Inc. (previously filed by the registrant on August 14, 2012 as Exhibit 3.1 to the registrant’s Quarterly Report on Form 10-Q and incorporated herein by reference).

4.4		Form of Common Stock Certificate of Sigma Labs, Inc. (previously filed by the registrant on September 23, 2014 as Exhibit 4.4 to the registrant’s registration statement on Form S-3 and incorporated herein by reference).

4.5		Form of Preferred Stock Certificate.*

4.6		Form of Warrant.*

4.7		Form of Warrant Agreement.*

4.8		Form of Indenture (previously filed by the registrant on September 23, 2014 as Exhibit 4.8 to the registrant’s registration statement on Form S-3 and incorporated herein by reference).

4.9		Form of Debt Security.*

4.10		Form of Unit Agreement.*

5.1		Opinion of TroyGould PC relating to the base prospectus included in this registration statement (previously filed by the registrant on September 23, 2014 as Exhibit 5.1 to the registrant’s registration statement on Form S-3 and incorporated herein by reference).

5.2		Opinion of TroyGould PC relating to the at-the-market offering prospectus included in this registration statement (previously filed by the registrant on September 23, 2014 as Exhibit 5.2 to the registrant’s registration statement on Form S-3 and incorporated herein by reference).

23.1		Consent of Pritchett, Siler & Hardy, P.C. (filed with this registration statement).

23.2		Consents of TroyGould PC (included in Exhibits 5.1 and 5.2).

24.1		Power of Attorney (included in Part II of the registration statement previously filed by the registrant on September 23, 2014 and incorporated herein by reference).

25.1		Statement of Eligibility of Trustee on Form T-1 under the Trust Indenture Act of 1939, as amended.**